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  • linux raid 1: right after replacing and syncing one drive, the other disk fails - understanding what is going on with mdstat/mdadm

    - by devicerandom
    We have an old RAID 1 Linux server (Ubuntu Lucid 10.04), with four partitions. A few days ago /dev/sdb failed, and today we noticed /dev/sda had pre-failure ominous SMART signs (~4000 reallocated sector count). We replaced /dev/sdb this morning and rebuilt the RAID on the new drive, following this guide: http://www.howtoforge.com/replacing_hard_disks_in_a_raid1_array Everything went smooth until the very end. When it looked like it was finishing to synchronize the last partition, the other old one failed. At this point I am very unsure of the state of the system. Everything seems working and the files seem to be all accessible, just as if it synchronized everything, but I'm new to RAID and I'm worried about what is going on. The /proc/mdstat output is: Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md3 : active raid1 sdb4[2](S) sda4[0] 478713792 blocks [2/1] [U_] md2 : active raid1 sdb3[1] sda3[2](F) 244140992 blocks [2/1] [_U] md1 : active raid1 sdb2[1] sda2[2](F) 244140992 blocks [2/1] [_U] md0 : active raid1 sdb1[1] sda1[2](F) 9764800 blocks [2/1] [_U] unused devices: <none> The order of [_U] vs [U_]. Why aren't they consistent along all the array? Is the first U /dev/sda or /dev/sdb? (I tried looking on the web for this trivial information but I found no explicit indication) If I read correctly for md0, [_U] should be /dev/sda1 (down) and /dev/sdb1 (up). But if /dev/sda has failed, how can it be the opposite for md3 ? I understand /dev/sdb4 is now spare because probably it failed to synchronize it 100%, but why does it show /dev/sda4 as up? Shouldn't it be [__]? Or [_U] anyway? The /dev/sda drive now cannot even be accessed by SMART anymore apparently, so I wouldn't expect it to be up. What is wrong with my interpretation of the output? I attach also the outputs of mdadm --detail for the four partitions: /dev/md0: Version : 00.90 Creation Time : Fri Jan 21 18:43:07 2011 Raid Level : raid1 Array Size : 9764800 (9.31 GiB 10.00 GB) Used Dev Size : 9764800 (9.31 GiB 10.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:27:33 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : a3b4dbbd:859bf7f2:bde36644:fcef85e2 Events : 0.7704 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 17 1 active sync /dev/sdb1 2 8 1 - faulty spare /dev/sda1 /dev/md1: Version : 00.90 Creation Time : Fri Jan 21 18:43:15 2011 Raid Level : raid1 Array Size : 244140992 (232.83 GiB 250.00 GB) Used Dev Size : 244140992 (232.83 GiB 250.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:39:06 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : 8bcd5765:90dc93d5:cc70849c:224ced45 Events : 0.1508280 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 18 1 active sync /dev/sdb2 2 8 2 - faulty spare /dev/sda2 /dev/md2: Version : 00.90 Creation Time : Fri Jan 21 18:43:19 2011 Raid Level : raid1 Array Size : 244140992 (232.83 GiB 250.00 GB) Used Dev Size : 244140992 (232.83 GiB 250.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:46:44 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : 2885668b:881cafed:b8275ae8:16bc7171 Events : 0.2289636 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 19 1 active sync /dev/sdb3 2 8 3 - faulty spare /dev/sda3 /dev/md3: Version : 00.90 Creation Time : Fri Jan 21 18:43:22 2011 Raid Level : raid1 Array Size : 478713792 (456.54 GiB 490.20 GB) Used Dev Size : 478713792 (456.54 GiB 490.20 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 3 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:19:20 2013 State : clean, degraded Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 Number Major Minor RaidDevice State 0 8 4 0 active sync /dev/sda4 1 0 0 1 removed 2 8 20 - spare /dev/sdb4 The active sync on /dev/sda4 baffles me. I am worried because if tomorrow morning I have to replace /dev/sda, I want to be sure what should I sync with what and what is going on. I am also quite baffled by the fact /dev/sda decided to fail exactly when the raid finished resyncing. I'd like to understand what is really happening. Thanks a lot for your patience and help. Massimo

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  • GRUB is not Booting Correctly

    - by msknapp
    I have a PC with three hard disks. Windows 7 is installed on the first, Ubuntu 14.04 is installed on the third. After I re-booted, it went straight to Windows 7. So I tried explicitly telling my PC to boot using the third hard disk, but that just takes me to the grub rescue prompt. I followed Scott Severence's instructions here to try and recover. Essentially, I updated grub, reinstalled grub, and then updated it again. After re-booting, absolutely nothing had changed. So instead I tried using the boot-repair tool. In the past it had failed for me, saying that I had programs running and it could not unmount drives, when I was running nothing. I never figured out how to solve that problem, but it went away when I bought another hard drive and used that for my Ubuntu installation, I don't know why. In any case, I ran the boot-repair tool and this time it said it was successful. First time for everything right? I re-booted, only to be taken straight to the grub rescue prompt. So I changed my BIOS settings to use the third hard disk for boot start up. That is the same hard drive where I have Ubuntu and grub installed, and the same one that the grub-repair tool told me to use. It still took me straight to the grub rescue prompt. So I went from not being able to boot Ubuntu, to not being able to boot either OS installed on my system. Thanks boot-repair! Boot repair gave me this URL for future troubleshooting: http://paste.ubuntu.com/8131669 When I try to boot from the third hard disk, this is my console: Loading Operating System ... error: attempt to read or write outside of disk 'hd0'. Entering rescue mode... grub rescue> grub rescue> set cmdpath=(hd0) prefix=(hd0,gpt2)/boot/grub root=hd0,gpt2 grub rescue> ls (hd0) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (hd1) (hd2) (hd2,gpt2) (hd2,gpt1) (hd3) Those values look correct to me. I have also experimented with changing some of those values, but 'insmod normal' always throws the same error. Somebody please tell me how to fix this. I have tried everything, reinstalling grub, and running boot-repair. =========================== Update: I think the problem might be that the ubuntu installer did not partition my hard disk correctly. I booted from live USB and then launched gparted and looked at how it partitioned things. This is what gparted says: Partition, File System, Size, Used, Unused, Flags /dev/sda1 (!), unknown, 1.00 MiB, ---, ---, bios_grub /dev/sda2, ext4, 2.71 TiB, 47.30 GiB, 2.67 TiB, /dev/sda3, linux-swap, 16.00 GiB, 0.00 B, 16.00 GiB, So that first line looks problematic. It is supposed to be the /boot partition. However, it was given only 1 MiB? I am assuming that MiB is actually supposed to mean megabyte, no idea why that 'i' is there. It also says the file system is unknown. I read the answer by andrew here, and he says he had to do a custom install, explicitly configuring the boot partition. So I think that maybe Ubuntu's installer has a bug in it, where it does not set up the boot partition correctly if you are not installing on the first hard disk in your computer. I am going to try reinstalling with a custom partition scheme. I read elsewhere (askubuntu won't let me post another link) that I don't even need a /boot partition any more. So instead of following Andrew's instructions ver batim, I'm first going to try having just two partitions: one for /, and another for my 16GB swap space. Both as primary partitions. The first will be formatted as ext4. If that doesn't work, I may try again using /boot. ======================== So I did my custom install with no /boot partition, and it did not work. When I rebooted, I had an error message saying that some address did not exist. So for the hundredth time, I booted from the live USB, and ran boot-repair. Now I get this message GPT detected. Please create a BIOS-Boot partition (>1MB, unformatted filesystem, bios_grub flag). This can be performed via tools such as Gparted. Then try again. I feel like I'm running in circles and nobody will help me.

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  • How do you re-mount an ext3 fs readwrite after it gets mounted readonly from a disk error?

    - by cagenut
    Its a relatively common problem when something goes wrong in a SAN for ext3 to detect the disk write errors and remount the filesystem read-only. Thats all well and good, only when the SAN is fixed I can't figure out how to re-re-mount the filesystem read-write without rebooting. Behold: [root@localhost ~]# multipath -ll mpath0 (36001f93000a310000299000200000000) dm-2 XIOTECH,ISE1400 [size=1.1T][features=1 queue_if_no_path][hwhandler=0][rw] \_ round-robin 0 [prio=2][active] \_ 1:0:0:1 sdb 8:16 [active][ready] \_ 2:0:0:1 sdc 8:32 [active][ready] [root@localhost ~]# mount /dev/mapper/mpath0 /mnt/foo [root@localhost ~]# touch /mnt/foo/blah All good, now I yank the LUN out from under it. [root@localhost ~]# touch /mnt/foo/blah [root@localhost ~]# touch /mnt/foo/blah touch: cannot touch `/mnt/foo/blah': Read-only file system [root@localhost ~]# tail /var/log/messages Mar 18 13:17:33 localhost multipathd: sdb: tur checker reports path is down Mar 18 13:17:34 localhost multipathd: sdc: tur checker reports path is down Mar 18 13:17:35 localhost kernel: Aborting journal on device dm-2. Mar 18 13:17:35 localhost kernel: Buffer I/O error on device dm-2, logical block 1545 Mar 18 13:17:35 localhost kernel: lost page write due to I/O error on dm-2 Mar 18 13:17:36 localhost kernel: ext3_abort called. Mar 18 13:17:36 localhost kernel: EXT3-fs error (device dm-2): ext3_journal_start_sb: Detected aborted journal Mar 18 13:17:36 localhost kernel: Remounting filesystem read-only It only thinks its read-only, in reality its not even there. [root@localhost ~]# multipath -ll sdb: checker msg is "tur checker reports path is down" sdc: checker msg is "tur checker reports path is down" mpath0 (36001f93000a310000299000200000000) dm-2 XIOTECH,ISE1400 [size=1.1T][features=0][hwhandler=0][rw] \_ round-robin 0 [prio=0][enabled] \_ 1:0:0:1 sdb 8:16 [failed][faulty] \_ 2:0:0:1 sdc 8:32 [failed][faulty] [root@localhost ~]# ll /mnt/foo/ ls: reading directory /mnt/foo/: Input/output error total 20 -rw-r--r-- 1 root root 0 Mar 18 13:11 bar How it still remembers that 'bar' file being there... mystery, but not important right now. Now I re-present the LUN: [root@localhost ~]# tail /var/log/messages Mar 18 13:23:58 localhost multipathd: sdb: tur checker reports path is up Mar 18 13:23:58 localhost multipathd: 8:16: reinstated Mar 18 13:23:58 localhost multipathd: mpath0: queue_if_no_path enabled Mar 18 13:23:58 localhost multipathd: mpath0: Recovered to normal mode Mar 18 13:23:58 localhost multipathd: mpath0: remaining active paths: 1 Mar 18 13:23:58 localhost multipathd: dm-2: add map (uevent) Mar 18 13:23:58 localhost multipathd: dm-2: devmap already registered Mar 18 13:23:59 localhost multipathd: sdc: tur checker reports path is up Mar 18 13:23:59 localhost multipathd: 8:32: reinstated Mar 18 13:23:59 localhost multipathd: mpath0: remaining active paths: 2 Mar 18 13:23:59 localhost multipathd: dm-2: add map (uevent) Mar 18 13:23:59 localhost multipathd: dm-2: devmap already registered [root@localhost ~]# multipath -ll mpath0 (36001f93000a310000299000200000000) dm-2 XIOTECH,ISE1400 [size=1.1T][features=1 queue_if_no_path][hwhandler=0][rw] \_ round-robin 0 [prio=2][enabled] \_ 1:0:0:1 sdb 8:16 [active][ready] \_ 2:0:0:1 sdc 8:32 [active][ready] Great right? It says [rw] right there. Not so fast: [root@localhost ~]# touch /mnt/foo/blah touch: cannot touch `/mnt/foo/blah': Read-only file system OK, doesn't do it automatically, I'll just give it a little push: [root@localhost ~]# mount -o remount /mnt/foo mount: block device /dev/mapper/mpath0 is write-protected, mounting read-only Noooooooooo. I have tried all sorts of different mount/tune2fs/dmsetup commands and I cannot figure out how to get it to un-flag the block device as write-protected. Rebooting will fix it, but I'd much rather do it on-line. An hour of googling has gotten me nowhere either. Save me ServerFault.

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  • How do you re-mount an ext3 fs readwrite after it gets mounted readonly from a disk error?

    - by cagenut
    Its a relatively common problem when something goes wrong in a SAN for ext3 to detect the disk write errors and remount the filesystem read-only. Thats all well and good, only when the SAN is fixed I can't figure out how to re-re-mount the filesystem read-write without rebooting. Behold: [root@localhost ~]# multipath -ll mpath0 (36001f93000a310000299000200000000) dm-2 XIOTECH,ISE1400 [size=1.1T][features=1 queue_if_no_path][hwhandler=0][rw] \_ round-robin 0 [prio=2][active] \_ 1:0:0:1 sdb 8:16 [active][ready] \_ 2:0:0:1 sdc 8:32 [active][ready] [root@localhost ~]# mount /dev/mapper/mpath0 /mnt/foo [root@localhost ~]# touch /mnt/foo/blah All good, now I yank the LUN out from under it. [root@localhost ~]# touch /mnt/foo/blah [root@localhost ~]# touch /mnt/foo/blah touch: cannot touch `/mnt/foo/blah': Read-only file system [root@localhost ~]# tail /var/log/messages Mar 18 13:17:33 localhost multipathd: sdb: tur checker reports path is down Mar 18 13:17:34 localhost multipathd: sdc: tur checker reports path is down Mar 18 13:17:35 localhost kernel: Aborting journal on device dm-2. Mar 18 13:17:35 localhost kernel: Buffer I/O error on device dm-2, logical block 1545 Mar 18 13:17:35 localhost kernel: lost page write due to I/O error on dm-2 Mar 18 13:17:36 localhost kernel: ext3_abort called. Mar 18 13:17:36 localhost kernel: EXT3-fs error (device dm-2): ext3_journal_start_sb: Detected aborted journal Mar 18 13:17:36 localhost kernel: Remounting filesystem read-only It only thinks its read-only, in reality its not even there. [root@localhost ~]# multipath -ll sdb: checker msg is "tur checker reports path is down" sdc: checker msg is "tur checker reports path is down" mpath0 (36001f93000a310000299000200000000) dm-2 XIOTECH,ISE1400 [size=1.1T][features=0][hwhandler=0][rw] \_ round-robin 0 [prio=0][enabled] \_ 1:0:0:1 sdb 8:16 [failed][faulty] \_ 2:0:0:1 sdc 8:32 [failed][faulty] [root@localhost ~]# ll /mnt/foo/ ls: reading directory /mnt/foo/: Input/output error total 20 -rw-r--r-- 1 root root 0 Mar 18 13:11 bar How it still remembers that 'bar' file being there... mystery, but not important right now. Now I re-present the LUN: [root@localhost ~]# tail /var/log/messages Mar 18 13:23:58 localhost multipathd: sdb: tur checker reports path is up Mar 18 13:23:58 localhost multipathd: 8:16: reinstated Mar 18 13:23:58 localhost multipathd: mpath0: queue_if_no_path enabled Mar 18 13:23:58 localhost multipathd: mpath0: Recovered to normal mode Mar 18 13:23:58 localhost multipathd: mpath0: remaining active paths: 1 Mar 18 13:23:58 localhost multipathd: dm-2: add map (uevent) Mar 18 13:23:58 localhost multipathd: dm-2: devmap already registered Mar 18 13:23:59 localhost multipathd: sdc: tur checker reports path is up Mar 18 13:23:59 localhost multipathd: 8:32: reinstated Mar 18 13:23:59 localhost multipathd: mpath0: remaining active paths: 2 Mar 18 13:23:59 localhost multipathd: dm-2: add map (uevent) Mar 18 13:23:59 localhost multipathd: dm-2: devmap already registered [root@localhost ~]# multipath -ll mpath0 (36001f93000a310000299000200000000) dm-2 XIOTECH,ISE1400 [size=1.1T][features=1 queue_if_no_path][hwhandler=0][rw] \_ round-robin 0 [prio=2][enabled] \_ 1:0:0:1 sdb 8:16 [active][ready] \_ 2:0:0:1 sdc 8:32 [active][ready] Great right? It says [rw] right there. Not so fast: [root@localhost ~]# touch /mnt/foo/blah touch: cannot touch `/mnt/foo/blah': Read-only file system OK, doesn't do it automatically, I'll just give it a little push: [root@localhost ~]# mount -o remount /mnt/foo mount: block device /dev/mapper/mpath0 is write-protected, mounting read-only The hell you are: [root@localhost ~]# mount -o remount,rw /mnt/foo mount: block device /dev/mapper/mpath0 is write-protected, mounting read-only Noooooooooo. I have tried all sorts of different mount/tune2fs/dmsetup commands and I cannot figure out how to get it to un-flag the block device as write-protected. Rebooting will fix it, but I'd much rather do it on-line. An hour of googling has gotten me nowhere either. Save me ServerFault.

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  • Mysql partitioning: Partitions outside of date range is included

    - by Sturlum
    Hi, I have just tried to configure partitions based on date, but it seems that mysql still includes a partition with no relevant data. It will use the relevant partition but also include the oldest for some reason. Am I doing it wrong? The version is 5.1.44 (MyISAM) I first added a few partitions based on "day", which is of type "date" ALTER TABLE ptest PARTITION BY RANGE(TO_DAYS(day)) ( PARTITION p1 VALUES LESS THAN (TO_DAYS('2009-08-01')), PARTITION p2 VALUES LESS THAN (TO_DAYS('2009-11-01')), PARTITION p3 VALUES LESS THAN (TO_DAYS('2010-02-01')), PARTITION p4 VALUES LESS THAN (TO_DAYS('2010-05-01')) ); After a query, I find that it uses the "old" partition, that should not contain any relevant data. mysql> explain partitions select * from ptest where day between '2010-03-11' and '2010-03-12'; +----+-------------+------------+------------+-------+---------------+------+---------+------+------+-------------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+------------+-------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | ptest | p1,p4 | range | day | day | 3 | NULL | 79 | Using where | +----+-------------+------------+------------+-------+---------------+------+---------+------+------+-------------+ When I select a single day, it works: mysql> explain partitions select * from ptest where day = '2010-03-11'; +----+-------------+------------+------------+------+---------------+------+---------+-------+------+-------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+------------+------+---------------+------+---------+-------+------+-------+ | 1 | SIMPLE | ptest | p4 | ref | day | day | 3 | const | 39 | | +----+-------------+------------+------------+------+---------------+------+---------+-------+------+-------+

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  • Reorganize Primary/Recovery Partitions and then install Ubuntu Netbook Remix?

    - by Wesley
    Hi all, I have a Samsung N120 netbook (with upgraded 2GB RAM). I recently got a new hard drive and motherboard for it because the original parts were faulty. However, when I got it back, whoever was working on it decided to make my primary partition ~40GB in size, compared to (what appears to be) the recovery partition, which is around 100GB in size. Firstly, I want to make the recovery partition much smaller (around ~10GB or smaller, if possible) and then make my primary partition fill the rest of the space. After that, I want to install Ubuntu Netbook Remix 9.10. I don't know if this is installed within Windows like Ubuntu 9.10 but I want both XP and UNR on my machine at the same time. So basically... how do I resize my primary and recovery partitions such that the recovery is about 10GB or less and the primary fills the rest? Secondly, is UNR installed within Windows? (If not, would it create its own partition on my hard drive, along with the XP partition, and the recovery partition?) Thanks in advance.

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  • Cannot Install Bootcamp on Mac Fusion Drive

    - by user3377019
    I have two drive installed in my mid-2013 Macbook pro. It is running osx maverick. I set the two drives (an ssd and a regular HD) up using the fusion drive (following the diy fusion drive guides out there). I went ahead and created a 40gb partition to host my windows install. I removed the SSD, installed windows, then reinstalled the SSD. As soon as the ssd was placed back in the bootcamp partition stopped booting. I get a blinking cursor on a black screen. I checked out the partition info in disk utility and it appears that the windows partition is not marked bootable. Below is some info I managed to gather. I am wondering if there is a way to fix the partition table so my bootcamp will boot. /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *120.0 GB disk0 1: EFI EFI 209.7 MB disk0s1 2: Apple_CoreStorage 119.7 GB disk0s2 3: Apple_Boot Boot OS X 134.2 MB disk0s3 /dev/disk1 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.1 GB disk1 1: EFI EFI 209.7 MB disk1s1 2: Microsoft Basic Data BOOTCAMP 40.0 GB disk1s2 3: Apple_CoreStorage 459.2 GB disk1s3 4: Apple_Boot Boot OS X 650.0 MB disk1s4 /dev/disk2 #: TYPE NAME SIZE IDENTIFIER 0: Apple_HFS Macintosh HD *573.4 GB disk2 Name : BOOTCAMP Type : Partition Disk Identifier : disk1s2 Mount Point : /Volumes/BOOTCAMP File System : Windows NT File System (NTFS) Connection Bus : SATA Device Tree : IODeviceTree:/PCI0@0/SATA@1F,2/PRT1@1/PMP@0 Writable : No Universal Unique Identifier : 584BAED6-4C46-4F18-93B3-957F6E27003C Capacity : 40 GB (39,998,980,096 Bytes) Free Space : 16.34 GB (16,339,972,096 Bytes) Used : 23.66 GB (23,659,003,904 Bytes) Number of Files : 86,424 Number of Folders : 0 Owners Enabled : No Can Turn Owners Off : No Can Be Formatted : No Bootable : No Supports Journaling : No Journaled : No Disk Number : 1 Partition Number : 2

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  • OS Missing? Messed up the MBR on Win7 64-bit

    - by hom3lesshom3boy
    I have a Windows 7 machine with two hard drives: a 1TB C: drive and 500GB J:. I had Windows XP installed on C: and Windows 7 installed on J:. I installed Windows 7 after Windows XP from an installer .exe I (legally) bought and downloaded. It, and all of my other files, are sitting on my J: drive intact. While under my Windows 7 install, a few days ago I decided to use Priform's CCleaner and use its DriveWipe utility to wipe the C: drive. 1% into the process, I cancelled and attempted to use it again. It gives me an error saying it can't format the drive, so I poke around the Internet a bit, give up, and restart my computer. I first get an "OS is missing" error after the computer boots past the BIOS. I downloaded and put UBCD on a bootable USB to use another drivewiping tool to completely erase the C: drive, hoping it'll take the problem with it. No luck. I try to use TestDisk to make my J: my primary active drive, but no luck. I still get the "OS is missing" error. Or sometimes it'll hang at Verifying DMI Pool. Or sometimes I'll get the "NTLDR is missing" error. I get hold of Hiren's and put it on another bootable USB. I first I tried the Boot Windows 7 from Hard Drive option, and I get "Error 15: File Not Found". I tried the "Fix 'NTLDR is Missing'" option (I'm not quite sure why this is even showing up, since I'm trying to get into a HDD with Windows 7 installed. Probably messed up somewhere when I used TestDisk) and I get this list: I'll run through the error messages I get: 1st Try - Windows could not start because the following file is missing or corrupt: \system32\hal.dll 2nd Try - Windows could not start because the following file is missing or corrupt: \system32\ntoskrnl.exe 3rd Try - Windows could not start because of a computer disk hardware configuration problem. Could not read from the selected boot disk. Check boot path and disk hardware. 4th - 8th Try - Same as #3 9th Try - I/O Error accessing boot sector file multi(0)disk(0)fdisk(0)\BOOTSEC.DOS. And computer freezes. 10th Try - computer restarts Needless to say, not a single one of those works. I then tried to open up the Windows 7 exe I have sitting on my J: from the Mini-XP OS on Hiren's, but it won't run because I'm trying to run a 64-bit file from a 32-bit exe. At least, that's the problem according to these guys: http://social.technet.microsoft.com/...-b2f54e9c7d18/ I then borrowed a 64-bit Windows Home Premium CD from a friend to get to the recovery options. But I get the error message: This version of System Recovery Options is not compatible with the version of Windows you are trying to repair. Try using a recovery disc that is compatible with this version of Windows. I pressed Shift + F10 to get to the Command Prompt directly. These are the exact steps I took from there (paraphrased a little): X:\Sources>bootrec /Fixmbr The operation completed successfully. X:\Sources>bootrec /Fixboot The operation completed successfully. I restarted my computer, but it still didn't work. I unplugged the C: drive, then tried bootrec and Diskpart: X:\Sources> bootrec.exe X:\Sources> bootrec /RebuildBcd Total identified Windows installations: 1 [1] \\?\GLOBALROOT\Device\HarddiskVolume1\Windows Add installation to bootlist? Yes(Y)/No(N)/All(A):y The requested system device cannot be found. X:\Sources>DiskPart DISKPART> List Disk Disk # Status Size Free Dyn Gpt Disk 0_Online_465GB_0B_______* Disk 1 Online 1000MB 0B (this is Hiren's on a bootable usb) DISKPART> Select Disk 0 Disk 0 is now the selected disk. DISKPART> List Partition Partition # Type Size Offset Partition 1 System 465GB 31KB DISKPART> Select Partition 1 Partition 1 is now the selected partition DISKPART> Active The selected disk is not a fixed MBR disk. The ACTIVE command can only be used on fixed MBR disks. DISKPART> exit Leaving Diskpart... X:\Sources>bootrec /Fixmbr The operation completed successfully. X:\Sources>bootrec /Fixboot The operation completed successfully. Before I go any further, is there anything I'm overlooking/doing wrong? All I care about is making the J: and Windows 7 bootable again. SPECS: Windows 7 Professional 64-Bit GIGABYTE - Motherboard - Socket 775 - GA-P35-DS3R (rev. 2.1) Crucial Ballistix 2048MB PC6400 DDR2 800MHz (2x2GB) Intel Core 2 Duo E6700 Processor (2.6 (6GHZ) I think... not sure anymore C: HDD - SAMSUNG HD103UJ (1TB, not plugged in) J: HDD - WDC WD5000AKS-00V1A0 (500GB)

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  • Windows 7 boots to black screen with blinking cursor

    - by murgatroid99
    I have an Alienware M17x that dual boots into Ubuntu 11.04 and Windows 7 Home Premium. Currently, the computer starts at the GRUB loader and will boot into Ubuntu, but if I try to boot into Windows, I immediately get a black screen with a blinking cursor in the upper left corner. The output of fdisk -l is Device Boot Start End Blocks Id System /dev/dm-0p1 1 5 40131 de Dell Utility Partition 1 does not start on physical sector boundary. /dev/dm-0p2 6 1918 15360000 7 HPFS/NTFS Partition 2 does not start on physical sector boundary. /dev/dm-0p3 * 1918 64772 504878877+ 7 HPFS/NTFS Partition 3 does not start on physical sector boundary. /dev/dm-0p4 64772 77827 104858625 5 Extended Partition 4 does not start on physical sector boundary. /dev/dm-0p5 64772 67204 19531008 83 Linux /dev/dm-0p6 67204 74498 58593536 83 Linux /dev/dm-0p7 74498 77577 24731648 83 Linux /dev/dm-0p8 77578 77827 2000128 82 Linux swap / Solaris I have used the Windows rescue CD, and run the automatic error fixer until it finds no errors. I have run chkdsk /R on both the main Windows 7 (/dev/dm-0p3) partition and the recovery partition (/dev/dm-0p2). I set the main Windows 7 partition to be active. I also tried running in the recovery console the commands bootrec /fixmbr bootrec /fixboot bootrec /rebuildbcd None of these helped and the last set of commands deletes grub, which I then have to reinstall from Ubuntu. I think the last thing I did in windows before this started was install the newest ATI driver for my video card. This would suggest using system restore, and I actually had a restore point earlier (after the problem started), but after whatever I did that restore point does not appear in the list on the recovery disk any more, so I cannot do a system restore. Is there anything else I can try to make Windows boot properly again? Edit: Running the suggested commands bootsect /nt60 c: bcdboot c:\windows /s c: was also ineffective.

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  • Partitioning & Linux

    - by Zac
    Every tutorial on Linux-based partitioning schemes (or, just partitioning in general) will tell you that a PC can have either 4 primary partitions, or 3 primaries and 1 extended. They will all also tell you that Linux (in my case, Ubuntu) can be installed on either. It's also come to my attention that it is not too atypical for FHS directories, such as usr/, tmp/, etc/, home/ or var/ to be mounted separately on other partitions. Several questions I am unable to find the answers to, purely for my own edification: (1) By "PC", are we really talking about common PC disk types, like IDE or SATA? I guess I'm wondering why PC uses are limited to 4 primaries or 3 primaries + 1 extended (2) I'm choking on some basic OS concepts: it is said that a partition can be mounted by a file system or an OS. So I assume this means I can somehow instruct Ubuntu to mount to 1 partition, and then any part of, say, ReiserFS, to be mounted to another partition? How? (3)(a) What about creating swap partitions? Is there too much of a good thing with swap partitioning? If I have 4GB RAM over 320GB disk, what should my swap partition size be, and why? (3)(b) Are swap files the only way to create swap partitions? Wouldn't a Linux partitioning utility allow me to define a partition as being for virtual memory only? (4) Why are partitions limited to being "mounted" by just OSes and file systems? Why couldn't I write a program to take up its own, say, 512 MB partition, and then have it invoked or uses by an OS installed on another partition? Thanks for shedding any light here... not critical that I know this stuff, but it's got me thinking incessantly. And when I think incessantly, I...can't......sleep....

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  • How to migrate WinXP from failing old HD to new one

    - by Péter Török
    Following this issue, we have all our important data backed up now. I also bought and installed a new replacement hard disk (WD 160GB PATA) as secondary (slave) drive. I created two primary NTFS partitions on it: a 40 GB system partition, and a 110GB data partition. In theory I could start reinstalling WinXP from scratch on the new system partition, then copying over all user data from the old drive to the new data partition. Once this is done, I could even throw away the old drive, or keep it just to see what happens. (Note: I don't want to clone the whole drive as it contains a dual boot setup with an old Linux installation which I don't need anymore, and anyway, a fresh reinstall would do WinXP good to get rid of many years' clutter.) However, I am lazy :-) The old HD is still functioning, the problem has not manifested again since. So I feel there is no need to hurry with a complete OS reinstall. What I don't know though is whether I will be able to install WinXP on the new system partition at a later stage without affecting the contents of the data partition on the same drive. If this is possible, I can just move over all our data to the new data partition to have it safe, then continue running WinXP from the old drive as long as it works. Does anyone see any problems/risks with this plan?

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  • Regarding partitions for dual-booting Ubuntu with pre-existing Windows 7

    - by Shasteriskt
    I have zero actual experience with configuring disk partitions and the stuff I have read for the past few hours have been confusing me a bit, so please bear with me. First of all, I'd like to explain what I'm setting to achieve: Windows 7 with: C:\ Windows 7 (pre-existing installation) D:\ Data (Already exists and has files already) Ubuntu 11 - Does not exist yet, but I already have a LiveCD in hand. \root directory for Ubuntu \home on its own partition I plan \swap on its own partition with around 8GB Here is the current situation: I have a single 500 GB hard-disk with Windows 7 x64 installed, and the current partition schemes is as follows: System Reserved: 100 MB (Primary, Active) C: 100 GB - Where Windows 7 is installed (Primary) D: 365 GB - Where my files are located, LOTS of free space (Primary) Now, I would like to shrink my D: drive and create around 40 GB of unallocated disk space for the Ubuntu installation, but here what's confusing me a bit: I'm thinking I would create an extended partition and subdivide it into 3 logical partitions for the Ubuntu setup I had in mind. (If you think my setup is a bad idea, please let me know & why. I also hope you can suggest a better one...) I am aware that I can only have up to 4 primary partitions, or 3 primary partitions with 1 extended parition max. Now, does the System Recovery portion count as one primary partition? I'm really new to these things and it is totally unclear to me. In shrinking my D: drive using Windows 7's Disk Management tool, I would get an unallocated free space which I don't know how to make an extended partition from. It seems like I can only create a primary partition from it, not an extended one. How do I go about it? (I'd also like to note, if it is of any importance, that I am trying to avoid using the option to install Ubuntu alongside Windows, and much rather prefer using the custom install where I can specify which drives I wish to use and stuff. Somehow I feel its safer that way.)

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  • How to setup RAID 1 with Intel RST on an existing Windows 7 system?

    - by instcode
    I'd like to setup RAID-1 using Intel Rapid Storage Technology on my Windows 7 64-bit system. I have an 1TB SATA HDD with Windows 7 system installed on the first primary partition (leftmost, ~200GB). The rest of this HDD is unallocated (~800GB). I bought another 2TB SATA, then created a primary partition (leftmost, ~500GB) and filled my data in. The rest of this HDD is unallocated (~1.5TB). A quick disk layout (XXX is the unallocated region): HDD1 (1TB): [ 200GB C:\ SYSTEM | XXXXXXXXXXXX ] HDD2 (2TB): [ 500GB Z:\ PROGRAM | XXXXXXXXXXXXXXXXXXXXXX ] Now, I want to create a 500GB RAID-1 partition (I'm not sure if using "partition" is correct here) on the rightmost of the 2 HDDs above without losing any existing data from both disks. Here is the expected layout: HDD1 (1TB): [ 200GB C:\ SYSTEM | XXXXXX | 500GB D:\ DATA - RAID-1 ] HDD2 (2TB): [ 500GB Z:\ PROGRAM | XXXXXXXXXXXXXXXX | 500GB D:\ DATA RAID-1] Let's not concern about data lost, is it possible to have that final layout using Intel RST? Previously, I tried this layout using dynamic disk & software RAID from Windows and it worked as expected, however, it's quite ugly in resynching after an OS failure that I don't want. If yes, is there a way to keep the data on existing partitions untouched or, at least, it should keep the SYSTEM partition safe (I'm okay if the PROGRAM partition has to be gone.)? Well, are there any strict/special steps I should follow when using the Intel RST manager in order to achieve that? If none of those questions above are "Yes", could you please suggest some other possible layouts that leave the C:SYSTEM partition untouched?

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  • e2fsck extremly slow, although enough memory exists

    - by kaefert
    I've got this external USB-Disk: kaefert@blechmobil:~$ lsusb -s 2:3 Bus 002 Device 003: ID 0bc2:3320 Seagate RSS LLC As can be seen in this dmesg output, there are some problems that prevents that disk from beeing mounted: kaefert@blechmobil:~$ dmesg | grep sdb [ 114.474342] sd 5:0:0:0: [sdb] 732566645 4096-byte logical blocks: (3.00 TB/2.72 TiB) [ 114.475089] sd 5:0:0:0: [sdb] Write Protect is off [ 114.475092] sd 5:0:0:0: [sdb] Mode Sense: 43 00 00 00 [ 114.475959] sd 5:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 114.477093] sd 5:0:0:0: [sdb] 732566645 4096-byte logical blocks: (3.00 TB/2.72 TiB) [ 114.501649] sdb: sdb1 [ 114.502717] sd 5:0:0:0: [sdb] 732566645 4096-byte logical blocks: (3.00 TB/2.72 TiB) [ 114.504354] sd 5:0:0:0: [sdb] Attached SCSI disk [ 116.804408] EXT4-fs (sdb1): ext4_check_descriptors: Checksum for group 3976 failed (47397!=61519) [ 116.804413] EXT4-fs (sdb1): group descriptors corrupted! So I went and fired up my favorite partition manager - gparted, and told it to verify and repair the partition sdb1. This made gparted call e2fsck (version 1.42.4 (12-Jun-2012)) e2fsck -f -y -v /dev/sdb1 Although gparted called e2fsck with the "-v" option, sadly it doesn't show me the output of my e2fsck process (bugreport https://bugzilla.gnome.org/show_bug.cgi?id=467925 ) I started this whole thing on Sunday (2012-11-04_2200) evening, so about 48 hours ago, this is what htop says about it now (2012-11-06-1900): PID USER PRI NI VIRT RES SHR S CPU% MEM% TIME+ Command 3704 root 39 19 1560M 1166M 768 R 98.0 19.5 42h56:43 e2fsck -f -y -v /dev/sdb1 Now I found a few posts on the internet that discuss e2fsck running slow, for example: http://gparted-forum.surf4.info/viewtopic.php?id=13613 where they write that its a good idea to see if the disk is just that slow because maybe its damaged, and I think these outputs tell me that this is not the case in my case: kaefert@blechmobil:~$ sudo hdparm -tT /dev/sdb /dev/sdb: Timing cached reads: 3562 MB in 2.00 seconds = 1783.29 MB/sec Timing buffered disk reads: 82 MB in 3.01 seconds = 27.26 MB/sec kaefert@blechmobil:~$ sudo hdparm /dev/sdb /dev/sdb: multcount = 0 (off) readonly = 0 (off) readahead = 256 (on) geometry = 364801/255/63, sectors = 5860533160, start = 0 However, although I can read quickly from that disk, this disk speed doesn't seem to be used by e2fsck, considering tools like gkrellm or iotop or this: kaefert@blechmobil:~$ iostat -x Linux 3.2.0-2-amd64 (blechmobil) 2012-11-06 _x86_64_ (2 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 14,24 47,81 14,63 0,95 0,00 22,37 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sda 0,59 8,29 2,42 5,14 43,17 160,17 53,75 0,30 39,80 8,72 54,42 3,95 2,99 sdb 137,54 5,48 9,23 0,20 587,07 22,73 129,35 0,07 7,70 7,51 16,18 2,17 2,04 Now I researched a little bit on how to find out what e2fsck is doing with all that processor time, and I found the tool strace, which gives me this: kaefert@blechmobil:~$ sudo strace -p3704 lseek(4, 41026998272, SEEK_SET) = 41026998272 write(4, "\212\354K[_\361\3nl\212\245\352\255jR\303\354\312Yv\334p\253r\217\265\3567\325\257\3766"..., 4096) = 4096 lseek(4, 48404766720, SEEK_SET) = 48404766720 read(4, "\7t\260\366\346\337\304\210\33\267j\35\377'\31f\372\252\ffU\317.y\211\360\36\240c\30`\34"..., 4096) = 4096 lseek(4, 41027002368, SEEK_SET) = 41027002368 write(4, "\232]7Ws\321\352\t\1@[+5\263\334\276{\343zZx\352\21\316`1\271[\202\350R`"..., 4096) = 4096 lseek(4, 48404770816, SEEK_SET) = 48404770816 read(4, "\17\362r\230\327\25\346//\210H\v\311\3237\323K\304\306\361a\223\311\324\272?\213\tq \370\24"..., 4096) = 4096 lseek(4, 41027006464, SEEK_SET) = 41027006464 write(4, "\367yy>x\216?=\324Z\305\351\376&\25\244\210\271\22\306}\276\237\370(\214\205G\262\360\257#"..., 4096) = 4096 lseek(4, 48404774912, SEEK_SET) = 48404774912 read(4, "\365\25\0\21|T\0\21}3t_\272\373\222k\r\177\303\1\201\261\221$\261B\232\3142\21U\316"..., 4096) = 4096 ^CProcess 3704 detached around 16 of these lines every second, so 4 read and 4 write operations every second, which I don't consider to be a lot.. And finally, my question: Will this process ever finish? If those numbers from fseek (48404774912) represent bytes, that would be something like 45 gigabytes, with this beeing a 3 terrabyte disk, which would give me 134 days to go, if the speed stays constant, and he scans the disk like this completly and only once. Do you have some advice for me? I have most of the data on that disk elsewhere, but I've put a lot of hours into sorting and merging it to this disk, so I would prefer to getting this disk up and running again, without formatting it anew. I don't think that the hardware is damaged since the disk is only a few months and since I can't see any I/O errors in the dmesg output. UPDATE: I just looked at the strace output again (2012-11-06_2300), now it looks like this: lseek(4, 1419860611072, SEEK_SET) = 1419860611072 read(4, "3#\f\2447\335\0\22A\355\374\276j\204'\207|\217V|\23\245[\7VP\251\242\276\207\317:"..., 4096) = 4096 lseek(4, 43018145792, SEEK_SET) = 43018145792 write(4, "]\206\231\342Y\204-2I\362\242\344\6R\205\361\324\177\265\317C\334V\324\260\334\275t=\10F."..., 4096) = 4096 lseek(4, 1419860615168, SEEK_SET) = 1419860615168 read(4, "\262\305\314Y\367\37x\326\245\226\226\320N\333$s\34\204\311\222\7\315\236\336\300TK\337\264\236\211n"..., 4096) = 4096 lseek(4, 43018149888, SEEK_SET) = 43018149888 write(4, "\271\224m\311\224\25!I\376\16;\377\0\223H\25Yd\201Y\342\r\203\271\24eG<\202{\373V"..., 4096) = 4096 lseek(4, 1419860619264, SEEK_SET) = 1419860619264 read(4, ";d\360\177\n\346\253\210\222|\250\352T\335M\33\260\320\261\7g\222P\344H?t\240\20\2548\310"..., 4096) = 4096 lseek(4, 43018153984, SEEK_SET) = 43018153984 write(4, "\360\252j\317\310\251G\227\335{\214`\341\267\31Y\202\360\v\374\307oq\3063\217Z\223\313\36D\211"..., 4096) = 4096 So this number of the lseeks before the reads, like 1419860619264 are already a lot bigger, standing for 1.29 terabytes if the numbers are bytes, so it doesn't seem to be a linear progress on a big scale, maybe there are only some areas that need work, that have big gaps in between them. (times are in CET)

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  • Hibernation fails; The system cannot find the file specified

    - by GMMan
    Recently I installed Ubuntu 12.04.1 LTS on my Lenovo Y480. Hibernation was working properly after the Ubuntu install, but I was making sure all of the operating systems on my system worked, including OneKey Recovery (recovery partition). It is of note that I installed Windows 7 from scratch with a disk image I downloaded off of my university's DreamSpark program, and further to that I had to image the partition with Paragon Backup & Recovery, repartition to convert the Windows partition to extended, install Ubuntu, and then restore the image. During that process I also used the Windows disc to edit the BCD as to reuse the existing entry for the restored partition. I also used the automated "repair your computer" option. With verification, I noticed that the "repair your computer" option actually wrote to the wrong BCD (the recovery partition), and I mounted the partition and restored the original BCD (from a copy I made earlier), and rebooted. At this point my GRUB broke, and I was able to restore it. At this point hibernation broke. I tried powercfg /h off and powercfg /h on, rebooted, and nothing. Also tried increasing the hibernation file size as directed on this post, but it still doesn't work. Executing shutdown /h yields The system cannot find the file specified.(2). What file? It seems that mounting the system partition sometimes works, but I don't want to keep it mounted in case it gets written to accidentally. How do I permanently fix this?

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  • Clone a Windows Installation to a 3TB Hard Drive; MBR to GPT

    - by DanBlakemore
    I have Windows 7 Professional 64-bit installed on my desktop. Unfortunately for me and my wallet my hard drive is failing. I have purchased a 3TB hard drive as a replacement for my current 2TB drive. I would like to avoid as much hassle as possible in moving to this new drive so I would like to copy my current partition to the new drive using Gparted. The problem is that I suspect that my current partition is MBR, and I need GPT on my new drive since it is 3TB. Can I simply copy the MBR partition onto the new disk and then convert it to GPT after the fact (can you even convert the type of a partition)? Or would I need to somehow copy the contents of the partition into a GPT partition on the new drive? How do I go about making this transistion? Also, are there any issues I should be wary of booting to a GPT partition? If it matters, my motherboard is 1 year old as of May, 2012. Edit: My motherboard is 1 day old. My old one does not have UEFI compatibility, so I decided to make an upgrade to Intel today given that I would need a UEFI motherboard to use my new HDD. How much can I use a dying hard drive (bad sectors according to Hitachi Drive Fitness Test)? I have assumed not at all, to be safe.

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  • Ubuntu 12.04 can't boot after installing with software RAID 1

    - by Bill
    I've been trying to install Ubuntu with software RAID on my server and there is obviously something that I don't understand about the process. This is the guide that I followed: https://help.ubuntu.com/11.04/serverguide/advanced-installation.html I have two identical 1 TB disks in my server. I went through the initial install process and manually set up my partitions. On each disk I set up: (1) 100 MB partition for EFI boot (I didn't originally have this but added it based on a forum post I found after my original install failed to boot, I ended up with EFIboot since that was what the 'guided partitioning' decided to do) (1) 970 MB partition for / (1) 30 MB partition for swap I then created new RAID 1 disks combining the two partitions, one from each disk, such that each partition is mirrored. I then configured their usage as stated above. After saving the configuration I said yes to boot in a degraded state. The rest of the setup went normally, no errors of any kind. I saw GRUB being installed and again no errors. However, after rebooting the server I get the dreaded 'Insert boot media' and nothing happens. I loaded up the recovery disk and the mdadm configuration looks correct. md0 is my EFIBoot partition md1 is my \ partition using ext4 md2 is my swap partition Running file -s /dev/md0 doesn't indicate that GRUB is there and so I attempted to reinstall GRUB using the recovery disk. I selected the md0 disk and it appeared to install just fine. Running file -s /dev/md1 shows the error needs journal recovery, I'm not sure if that's related or not or how to fix that. Rebooting gives me the same problem, no boot media found. I've searched around the internet but can't figure out what to do next or more importantly how to troubleshoot what exactly is going wrong. Thanks!

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  • How can I recover my data from a damaged hard drive?

    - by krk
    a few days ago when I was working on windows my laptop was beaten on the side where the hard drive is located. As a result, it was damaged and I couldn't access the windows partition. I had to boot the linux one, which is working without any trouble. I have 2 partition formatted with ntfs, the one with windows on it, and the other one intended to store data. I mounted the windows partition from ubuntu and I could see all my files. But when I tried to mount the data partition it was impossible. It threw me an error, it couldn't recognize ntfs partition. I try to copy the damaged disk into an external hard drive using the command: dd if=/dev/sda of=/dev/sdb conv=noerror,sync The progress stopped at 60%. I was still unable to mount the data partition. Now I'm trying to backup my files using an utility called Photorec. The problem is that it is recovering my files in a disorderly way, it is all mixed up and I need my original directory structure, it will become an endless task to organize the files as they were before. Is there any way I can get my partition back?

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  • Analytic functions – they’re not aggregates

    - by Rob Farley
    SQL 2012 brings us a bunch of new analytic functions, together with enhancements to the OVER clause. People who have known me over the years will remember that I’m a big fan of the OVER clause and the types of things that it brings us when applied to aggregate functions, as well as the ranking functions that it enables. The OVER clause was introduced in SQL Server 2005, and remained frustratingly unchanged until SQL Server 2012. This post is going to look at a particular aspect of the analytic functions though (not the enhancements to the OVER clause). When I give presentations about the analytic functions around Australia as part of the tour of SQL Saturdays (starting in Brisbane this Thursday), and in Chicago next month, I’ll make sure it’s sufficiently well described. But for this post – I’m going to skip that and assume you get it. The analytic functions introduced in SQL 2012 seem to come in pairs – FIRST_VALUE and LAST_VALUE, LAG and LEAD, CUME_DIST and PERCENT_RANK, PERCENTILE_CONT and PERCENTILE_DISC. Perhaps frustratingly, they take slightly different forms as well. The ones I want to look at now are FIRST_VALUE and LAST_VALUE, and PERCENTILE_CONT and PERCENTILE_DISC. The reason I’m pulling this ones out is that they always produce the same result within their partitions (if you’re applying them to the whole partition). Consider the following query: SELECT     YEAR(OrderDate),     FIRST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING),     LAST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING),     PERCENTILE_CONT(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)),     PERCENTILE_DISC(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)) FROM Sales.SalesOrderHeader ; This is designed to get the TotalDue for the first order of the year, the last order of the year, and also the 95% percentile, using both the continuous and discrete methods (‘discrete’ means it picks the closest one from the values available – ‘continuous’ means it will happily use something between, similar to what you would do for a traditional median of four values). I’m sure you can imagine the results – a different value for each field, but within each year, all the rows the same. Notice that I’m not grouping by the year. Nor am I filtering. This query gives us a result for every row in the SalesOrderHeader table – 31465 in this case (using the original AdventureWorks that dates back to the SQL 2005 days). The RANGE BETWEEN bit in FIRST_VALUE and LAST_VALUE is needed to make sure that we’re considering all the rows available. If we don’t specify that, it assumes we only mean “RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW”, which means that LAST_VALUE ends up being the row we’re looking at. At this point you might think about other environments such as Access or Reporting Services, and remember aggregate functions like FIRST. We really should be able to do something like: SELECT     YEAR(OrderDate),     FIRST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING) FROM Sales.SalesOrderHeader GROUP BY YEAR(OrderDate) ; But you can’t. You get that age-old error: Msg 8120, Level 16, State 1, Line 5 Column 'Sales.SalesOrderHeader.OrderDate' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. Msg 8120, Level 16, State 1, Line 5 Column 'Sales.SalesOrderHeader.SalesOrderID' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. Hmm. You see, FIRST_VALUE isn’t an aggregate function. None of these analytic functions are. There are too many things involved for SQL to realise that the values produced might be identical within the group. Furthermore, you can’t even surround it in a MAX. Then you get a different error, telling you that you can’t use windowed functions in the context of an aggregate. And so we end up grouping by doing a DISTINCT. SELECT DISTINCT     YEAR(OrderDate),         FIRST_VALUE(TotalDue)              OVER (PARTITION BY YEAR(OrderDate)                   ORDER BY OrderDate, SalesOrderID                   RANGE BETWEEN UNBOUNDED PRECEDING                             AND UNBOUNDED FOLLOWING),         LAST_VALUE(TotalDue)             OVER (PARTITION BY YEAR(OrderDate)                   ORDER BY OrderDate, SalesOrderID                   RANGE BETWEEN UNBOUNDED PRECEDING                             AND UNBOUNDED FOLLOWING),     PERCENTILE_CONT(0.95)          WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)),     PERCENTILE_DISC(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)) FROM Sales.SalesOrderHeader ; I’m sorry. It’s just the way it goes. Hopefully it’ll change the future, but for now, it’s what you’ll have to do. If we look in the execution plan, we see that it’s incredibly ugly, and actually works out the results of these analytic functions for all 31465 rows, finally performing the distinct operation to convert it into the four rows we get in the results. You might be able to achieve a better plan using things like TOP, or the kind of calculation that I used in http://sqlblog.com/blogs/rob_farley/archive/2011/08/23/t-sql-thoughts-about-the-95th-percentile.aspx (which is how PERCENTILE_CONT works), but it’s definitely convenient to use these functions, and in time, I’m sure we’ll see good improvements in the way that they are implemented. Oh, and this post should be good for fellow SQL Server MVP Nigel Sammy’s T-SQL Tuesday this month.

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  • Why Are Minimized Programs Often Slow to Open Again?

    - by Jason Fitzpatrick
    It seems particularly counterintuitive: you minimize an application because you plan on returning to it later and wish to skip shutting the application down and restarting it later, but sometimes maximizing it takes even longer than launching it fresh. What gives? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader Bart wants to know why he’s not saving any time with application minimization: I’m working in Photoshop CS6 and multiple browsers a lot. I’m not using them all at once, so sometimes some applications are minimized to taskbar for hours or days. The problem is, when I try to maximize them from the taskbar – it sometimes takes longer than starting them! Especially Photoshop feels really weird for many seconds after finally showing up, it’s slow, unresponsive and even sometimes totally freezes for minute or two. It’s not a hardware problem as it’s been like that since always on all on my PCs. Would I also notice it after upgrading my HDD to SDD and adding RAM (my main PC holds 4 GB currently)? Could guys with powerful pcs / macs tell me – does it also happen to you? I guess OSes somehow “focus” on active software and move all the resources away from the ones that run, but are not used. Is it possible to somehow set RAM / CPU / HDD priorities or something, for let’s say, Photoshop, so it won’t slow down after long period of inactivity? So what is the deal? Why does he find himself waiting to maximize a minimized app? The Answer SuperUser contributor Allquixotic explains why: Summary The immediate problem is that the programs that you have minimized are being paged out to the “page file” on your hard disk. This symptom can be improved by installing a Solid State Disk (SSD), adding more RAM to your system, reducing the number of programs you have open, or upgrading to a newer system architecture (for instance, Ivy Bridge or Haswell). Out of these options, adding more RAM is generally the most effective solution. Explanation The default behavior of Windows is to give active applications priority over inactive applications for having a spot in RAM. When there’s significant memory pressure (meaning the system doesn’t have a lot of free RAM if it were to let every program have all the RAM it wants), it starts putting minimized programs into the page file, which means it writes out their contents from RAM to disk, and then makes that area of RAM free. That free RAM helps programs you’re actively using — say, your web browser — run faster, because if they need to claim a new segment of RAM (like when you open a new tab), they can do so. This “free” RAM is also used as page cache, which means that when active programs attempt to read data on your hard disk, that data might be cached in RAM, which prevents your hard disk from being accessed to get that data. By using the majority of your RAM for page cache, and swapping out unused programs to disk, Windows is trying to improve responsiveness of the program(s) you are actively using, by making RAM available to them, and caching the files they access in RAM instead of the hard disk. The downside of this behavior is that minimized programs can take a while to have their contents copied from the page file, on disk, back into RAM. The time increases the larger the program’s footprint in memory. This is why you experience that delay when maximizing Photoshop. RAM is many times faster than a hard disk (depending on the specific hardware, it can be up to several orders of magnitude). An SSD is considerably faster than a hard disk, but it is still slower than RAM by orders of magnitude. Having your page file on an SSD will help, but it will also wear out the SSD more quickly than usual if your page file is heavily utilized due to RAM pressure. Remedies Here is an explanation of the available remedies, and their general effectiveness: Installing more RAM: This is the recommended path. If your system does not support more RAM than you already have installed, you will need to upgrade more of your system: possibly your motherboard, CPU, chassis, power supply, etc. depending on how old it is. If it’s a laptop, chances are you’ll have to buy an entire new laptop that supports more installed RAM. When you install more RAM, you reduce memory pressure, which reduces use of the page file, which is a good thing all around. You also make available more RAM for page cache, which will make all programs that access the hard disk run faster. As of Q4 2013, my personal recommendation is that you have at least 8 GB of RAM for a desktop or laptop whose purpose is anything more complex than web browsing and email. That means photo editing, video editing/viewing, playing computer games, audio editing or recording, programming / development, etc. all should have at least 8 GB of RAM, if not more. Run fewer programs at a time: This will only work if the programs you are running do not use a lot of memory on their own. Unfortunately, Adobe Creative Suite products such as Photoshop CS6 are known for using an enormous amount of memory. This also limits your multitasking ability. It’s a temporary, free remedy, but it can be an inconvenience to close down your web browser or Word every time you start Photoshop, for instance. This also wouldn’t stop Photoshop from being swapped when minimizing it, so it really isn’t a very effective solution. It only helps in some specific situations. Install an SSD: If your page file is on an SSD, the SSD’s improved speed compared to a hard disk will result in generally improved performance when the page file has to be read from or written to. Be aware that SSDs are not designed to withstand a very frequent and constant random stream of writes; they can only be written over a limited number of times before they start to break down. Heavy use of a page file is not a particularly good workload for an SSD. You should install an SSD in combination with a large amount of RAM if you want maximum performance while preserving the longevity of the SSD. Use a newer system architecture: Depending on the age of your system, you may be using an out of date system architecture. The “system architecture” is generally defined as the “generation” (think generations like children, parents, grandparents, etc.) of the motherboard and CPU. Newer generations generally support faster I/O (input/output), better memory bandwidth, lower latency, and less contention over shared resources, instead providing dedicated links between components. For example, starting with the “Nehalem” generation (around 2009), the Front-Side Bus (FSB) was eliminated, which removed a common bottleneck, because almost all system components had to share the same FSB for transmitting data. This was replaced with a “point to point” architecture, meaning that each component gets its own dedicated “lane” to the CPU, which continues to be improved every few years with new generations. You will generally see a more significant improvement in overall system performance depending on the “gap” between your computer’s architecture and the latest one available. For example, a Pentium 4 architecture from 2004 is going to see a much more significant improvement upgrading to “Haswell” (the latest as of Q4 2013) than a “Sandy Bridge” architecture from ~2010. Links Related questions: How to reduce disk thrashing (paging)? Windows Swap (Page File): Enable or Disable? Also, just in case you’re considering it, you really shouldn’t disable the page file, as this will only make matters worse; see here. And, in case you needed extra convincing to leave the Windows Page File alone, see here and here. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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  • Can't install Ubuntu 11.10 on a seperate disk partition. I have a log file. Please help!

    - by les02jen17
    Before I installed Ubuntu, I resized my C: drive (which has my Windows 7 OS). Prior to resizing, I even defragged the said drive. I tried using Wubi to install it on the created partition, but I receive an error. I have the log file and I would post it but it's too long and the site won't let me. :(So anyway, I wasn't able to install it, so I uninstalled it. Upon uninstalling Wubi and Ubuntu, I tried installing it by having the CD to my CD ROM. The installation was a success, however, upon rebooting I can neither boot to Ubuntu OR Windows 7. I get stuck in an infinite bootloop. I hope you can help me out! :(

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  • I need to write a program that reads angles in radians from an input disk and converts them in degre

    - by Amadou
    Write a program that reads angles in radians from an input disk le and converts them into degrees, minutes, and seconds. Output should be written into another le. A sample input le could be: # this is a comment # your program should be able to skip comment lines # and blank lines # input radian numbers could be seperated by blanks 0.0 1.0 # or by a newline 3.141593 6.0

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  • Is it possible to gzip and upload this string to Amazon S3 without ever being written to disk?

    - by BigJoe714
    I know this is probably possible using Streams, but I wasn't sure the correct syntax. I would like to pass a string to the Save method and have it gzip the string and upload it to Amazon S3 without ever being written to disk. The current method inefficiently reads/writes to disk in between. The S3 PutObjectRequest has a constructor with InputStream input as an option. import java.io.*; import java.util.zip.GZIPOutputStream; import com.amazonaws.auth.PropertiesCredentials; import com.amazonaws.services.s3.AmazonS3; import com.amazonaws.services.s3.AmazonS3Client; import com.amazonaws.services.s3.model.PutObjectRequest; public class FileStore { public static void Save(String data) throws IOException { File file = File.createTempFile("filemaster-", ".htm"); file.deleteOnExit(); Writer writer = new OutputStreamWriter(new FileOutputStream(file)); writer.write(data); writer.flush(); writer.close(); String zippedFilename = gzipFile(file.getAbsolutePath()); File zippedFile = new File(zippedFilename); zippedFile.deleteOnExit(); AmazonS3 s3 = new AmazonS3Client(new PropertiesCredentials( new FileInputStream("AwsCredentials.properties"))); String bucketName = "mybucket"; String key = "test/" + zippedFile.getName(); s3.putObject(new PutObjectRequest(bucketName, key, zippedFile)); } public static String gzipFile(String filename) throws IOException { try { // Create the GZIP output stream String outFilename = filename + ".gz"; GZIPOutputStream out = new GZIPOutputStream(new FileOutputStream(outFilename)); // Open the input file FileInputStream in = new FileInputStream(filename); // Transfer bytes from the input file to the GZIP output stream byte[] buf = new byte[1024]; int len; while ((len = in.read(buf)) > 0) { out.write(buf, 0, len); } in.close(); // Complete the GZIP file out.finish(); out.close(); return outFilename; } catch (IOException e) { throw e; } } }

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