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• What is the quickest and safest way to test new software and revert all changes, if needed?

  - by calbar

  I'm looking for Windows software that will allow me to quickly create a "checkpoint", do whatever I might need to do to my computer - install programs/drivers/updates, create/delete personal files, reboot the system multiple times, open questionable attachments - and then revert the entire system back to when the checkpoint was created. Essentially I want Windows Restore Points that save my personal files and partitions, too. It sounds like disk imaging might be the ticket, but creating them is much too slow and the restore process too involved... I'm hoping to sacrifice full disaster recovery for speed. Creating a checkpoint should be as close to one-click as possible, and rolling back should be a matter of selecting a restore point and rebooting. Ding! I'm familiar with Sandboxie, True Image Home "Try and Decide", Returnil, and a number of other "virtual system" apps that actively "catch" changes and allow you to commit or reject them. I'm not interested in these for a number of reasons - I prefer the "cut and dry" restore point approach. Finally, I'll note that I've just recently become aware of Comodo Time Machine. It sounds absolutely perfect, however, a quick skim through the user forums show more than a few horror stories of corrupted, unbootable systems. Any positive personal experience with the software to suppress my superstitions, or suggestions for more established alternatives would be greatly appreciated - Comodo Time Machine seems relatively new. Thanks for your help!

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• Can't mount Linux usb disk. It just create /dev/sg device but no /dev/sd

  - by MTilsted

  I have a Corsair R60 ssd disk which is a disk with both sata and usb connectors. But the usb thing seems to be a bit non-standard, or maybe its just my fedora linux. When I insert the disk using a usb cabel to a running Fedora 14 linux system, a device called /dev/sg3 is added but that is all. No new /dev/sd* device is created so I can't mount the disk. If I look at cat /proc/scsi/sg/device_strs I get ATA Hitachi HTS54321 FB2O HL-DT-ST DVDRAM GSA-T50N RP05 Seagate Desktop 0130 Corsair CSSD-R60GB2 So the disk is there. (The last entry) but my linux will for some reason not see it as a usb hard disk. When I insert other usb disks they work fine. It is only this specific disk which causes problems. I have tried on 3 different computers with the same result. A hint to the problem may be that if I add the disk to a windows system(With usb) the disk is called "A fixed disk" and not a portable disk as expected. The disk works fine with linux If i connect it with the sata cabel, but I would really like to have it working with usb too. (To mount it on computers without sata). Added: I did try to mount /dev/sg3 but mount say that its not a block device. (File say Its a character special device). Added output from dmesg: [ 97.454073] usb 7-1: USB disconnect, address 2 [ 105.913055] hub 2-0:1.0: unable to enumerate USB device on port 3 [ 107.048054] usb 2-3: new high speed USB device using ehci_hcd and address 5 [ 107.162900] usb 2-3: New USB device found, idVendor=1b1c, idProduct=1ab8 [ 107.162903] usb 2-3: New USB device strings: Mfr=1, Product=2, SerialNumber=5 [ 107.162906] usb 2-3: Product: CSSD-R60GB2 [ 107.162908] usb 2-3: Manufacturer: Corsair [ 107.162910] usb 2-3: SerialNumber: 10111441000000990069 [ 107.167651] scsi7 : usb-storage 2-3:1.0 [ 108.195543] scsi 7:0:0:0: Direct-Access Corsair CSSD-R60GB2 PQ: 1 ANSI: 0 [ 108.197732] scsi 7:0:0:0: Attached scsi generic sg3 type 0

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• ssh works fine when using public interface, but slow when using private interface

  - by Kevin M

  My Linux(UbuntuEEE) to Linux(CentOS) ssh takes a long time to log in(~15 seconds) when using the private interface, but not when using the public one. I have a Linux box acting as my router. As such, it has multiple interfaces(75.xxx.xxx.xxx, 192.168.1.1). I can ssh in from the internal interface(192.168.1.65 to .1), but it will take a while. I can ssh into the public address, and it goes quickly(~1 second). I have another box that I can ssh into the inside interface from and it goes quickly. iptables is set to accept packets coming into the interface immediately. sshd's UseDNS is normally on; I get the same problem if I turn it off and restart sshd. I normally use public-key authentication; I have done a mv ~/.ssh/ ~/ssh/ and it will ask me for a password after going slowly. After logging in(using either interface), speed is quick. ssh client version(via ssh -v):OpenSSH_4.7p1 Debian-8ubuntu1.2, OpenSSL 0.9.8g 19 Oct 2007 ssh server version(via rpm -qv openssh_server):openssh-server-4.3p2-29.el5

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• UW-IMAP server, high load for one user

  - by Bruce Garlock

  We have been experiencing a very strange anomaly, with one specific user with our UW-IMAP server. We have about 75 users using the server, and one particular user, who is in about the middle as far as used storage keeps having issues with slow speed. Most of our users all use Thunderbird 2, or Thunderbird 3. Mostly 2, because of the performance issues we have had with 3. This user was on 3, and I downgraded him to 2. The performance has gotten better, but according to the imapd processes on the server, his username is using the most CPU % and CPU time. I've already done all the usual T/S'ing: Started profile from scratch, compacted folders, re-indexed, newer faster computer, etc.. Still, this users' imapd process is always using the most CPU on the server. For troubleshooting, we setup another user which has more usage, folders, etc.. than he does, but we don't see the users process taking up most of the CPU with the imapd process. So, it almost sounds like a particular email may be the culprit, but how can we find it, if thats the problem? This has been going on for a while, and he is a management person, so his patience is about to end. Does anyone have any ideas?

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• xen + debian network after upgrade squeeze to wheeze

  - by rush

  I've got a Debian + Xen server. After a system upgrade to the stable version the network doesn't come up after boot. Every time after reboot I need to bring it up manually. The network configuration was not changed during upgrade. Here is /etc/network/interfaces: auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 11.22.33.44 netmask 255.255.255.0 gateway 11.22.33.1 nameserver 8.8.8.8 After boot ip r shows no route and eth0 has no ip address. Manually ip and route setup goes fine and network starts working. Messages from dmesg about network I've found (looks like nothing interesting) [ 3.894401] ACPI: Fan [FAN3] (off) [ 3.894444] ACPI: Fan [FAN4] (off) [ 4.178348] e1000e 0000:00:19.0: eth0: (PCI Express:2.5GT/s:Width x1) 00:1e:67:14:66:c9 [ 4.178351] e1000e 0000:00:19.0: eth0: Intel(R) PRO/1000 Network Connection [ 4.178392] e1000e 0000:00:19.0: eth0: MAC: 10, PHY: 11, PBA No: 0100FF-0FF [ 4.178413] e1000e 0000:02:00.0: Disabling ASPM L0s L1 [ 4.178432] xen: registering gsi 16 triggering 0 polarity 1 -- [ 4.223667] ata5: DUMMY [ 4.223668] ata6: DUMMY [ 4.289153] e1000e 0000:02:00.0: eth1: (PCI Express:2.5GT/s:Width x1) 00:1e:67:14:66:c8 [ 4.289155] e1000e 0000:02:00.0: eth1: Intel(R) PRO/1000 Network Connection [ 4.289245] e1000e 0000:02:00.0: eth1: MAC: 3, PHY: 8, PBA No: 1000FF-0FF [ 4.506908] usb 1-1: new high-speed USB device number 2 using ehci_hcd [ 4.542920] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300) -- [ 10.362999] EXT4-fs (dm-23): mounted filesystem with ordered data mode. Opts: (null) [ 10.419103] EXT4-fs (dm-3): mounted filesystem with ordered data mode. Opts: (null) [ 10.988255] ADDRCONF(NETDEV_UP): eth1: link is not ready [ 13.175533] Event-channel device installed. [ 13.287555] XENBUS: Unable to read cpu state -- [ 13.288670] XENBUS: Unable to read cpu state [ 13.965939] Bridge firewalling registered [ 14.134048] e1000e: eth1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx [ 14.283862] ADDRCONF(NETDEV_UP): peth0: link is not ready [ 14.284543] ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready [ 17.800627] e1000e: peth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx [ 17.801377] ADDRCONF(NETDEV_CHANGE): peth0: link becomes ready [ 18.307278] device peth0 entered promiscuous mode [ 24.538899] eth1: no IPv6 routers present [ 28.570902] peth0: no IPv6 routers present I've upgraded two servers and I've such behaviour on two of them. How to fix this and get network starts automatically on boot?

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• Router vs switch in a LAN [closed]

  - by servernewbie

  If I have a LAN and and connect it with a switch, I understand it uses a CAM table to route packets in layer 2 (by saving mac to port relations). So far all good. However, when using a router for a LAN (ONLY for a LAN, not to connect it to "the outside" WAN/internet/etc) I get a bit confused as to how it internally processes packets. I would first split this into two router scenarios: Router with buit-in switch In this scenario, I would expect that it will act exactly as a switch with a CAM table internally. This would probably benefit a bit in speed (guessing here?) compared to the next option. Router without built-in switch Here is where I get confused. If hostA wants to send a packet to hostB, it will ARP to find hostB's MAC address and send it there. Now, if we had a switch (above scenario) this would be easy. But how does it work now in a router WITHOUT a switch? If I would guess, hostA would send an Ethernet frame with hostB's MAC address to the line. The router would fetch the packet (even though the router has another MAC address, it would still fetch this packet even if it only contains hostB's MAC address). It would strip the Ethernet frame header and check the IP, and then check its own internal ARP table again for the MAC address. Now, this would seem like a waste of resources compared to a router with a built-in switch. But maybe it does not work like that at all. Does it also contain a CAM table? If that would be true, what would then the difference between these two routers really be?

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• why would resetting the Netgear N300 router fix my Win 7 laptop's slow wifi?

  - by rjnagle

  In the past day the wifi download speeds of my Win 7 HP 64 bit laptop have slowed considerably. I am trying to troubleshoot the problem and to figure out whether it's hardware related (i.e., is the Intel(R) Centrino(R) Wireless-N 2230 the problem?) or router related. I have a Netgear N300 router connected to my modem. I'm using Speedtest to measure my speed. First, during my problem state, my ipad can download and upload at normal speeds. It's only my Win 7 laptop which is having problems. Because my ipad downloads at normal speeds, that would tell me that the problem is specific to the laptop (either HW or SW). But when I restarted my Netgear router, the laptop wifi problems disappeared. That just doesn't make sense. If we know that one device can connect properly to the router, why would a laptop have problems? What are some possible reasons why this might happen? Also, during my problem state, I noticed that on my laptop upload speeds were faster than my download speeds. Anybody have a guess about what might cause upload speeds on one device to be faster than another? Is there any actions i could take (or options to enable) so this problem won't occur. (I initially thought my problem might be software related or memory related -- Norton AV or browser plugins. But even after I disabled everything and made sure memory footprint was minimal, the slowdown was still occurring -- and it solved itself altogether when the router was reset).

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• Troubleshooting my internet connection

  - by Simon Verbeke

  While I was out of the house, my father rearranged the network cables a bit. I don't know what he has done exactly - He says nothing more then pulling and untangling. When I came back home, my internet connection changed its IP from 192.168.0.205 to 169.254.197.233. The speed changed from 1Gbps to 10Mbps. It has also been at 100Mbps for a while. My subnetmask changed from 255.255.255.0 to 255.255.0.0. The standard gateway changed from 192.168.0.1 to no standard gateway. My DNS servers remain the same. I have checked the lights of the UTP ports, and it looks like it's only sending a heartbeat every few seconds. A sketch of the (relevant part of) the network: My PC ----- extender ----- modem ^ ^ ^ Wired | Wired | This thing connects two cables to each other All the cabling is gigabit, my network card is a Realtek RTL8168C(P)/8111(P) Family PCI-E Gigabit Ethernet NIC (NDIS 6.20). THe modem is a CBN SVG6540E I have no idea what is going on here and I don't know how to find out either. Any help is welcome! If you need any more info, please ask.

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• Is there an objective way to measure slowness of PC/WINDOWS?

  - by ekms

  We've a lot of users that usually complain about that his PC is "slow". (we use win XP). We usually check startup programs, virus, fragmentation, disk health and common problems that causes slowness (Symantec AV drops disk to 1mb/s , or a seagate HD firmware error in certain models), but in those cases the slowness is pretty evident. In other hand, the most common is the user complaining about his pc but for us looks OK, even in 6 years old desktops. People sometimes even complains about his new quad core desktops speed!!! So, we are asking if there's a way to OBJECTIVELY check that a computer didn't dropped its performance, compared with similar ones o previous measures, specially for work use (I don't think that 3dmark benchmark o similar may help). The only thing that I found that was useful is HDTune, but it only check hard disk performance. Basically, what we want is something that enable us to say to our users "see? your PC is as slow as was three years ago! stop complaining! Is all in your head!"

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• Network switches for LAN party

  - by guywhoneedsahand

  I am working on setting up the network for a small LAN party (less than 16 people). Most of them do not have wireless cards in their rigs, so I need to set up some way for everyone to a) play LAN games and b) access the internet. The LAN party will probably take place in my basement, where I have enough space. However, the basement is not wired up with the router which is actually on the floor above. I make a cantenna a while back that can boost the wireless performance of my computer significantly. How can I use this to provide internet and LAN to guests? My hope was that I could use a switch like this http://www.newegg.com/Product/Product.aspx?Item=N82E16833181166 for the LAN - but how can I give people access to the internet? Is there such thing as a network extender / 16-port switch? Obviously, the internet performance doesn't need to be super stellar, because the games will be using LAN - so I am looking to provide some usable internet for web browsing, and very high speed LAN for games. Thanks!

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• Remote Desktop Services Licensing - Does server have to have a RDS role?

  - by transistor1

  I recently set up a "micro" size Windows 2008 Datacenter server on Amazon AWS. My small group needs several concurrent RDS users to be able to access the machine. Without installing the "Remote Desktop Server" role, it allows 2 concurrent connections. I read on MS' website that in order to set up multiple users, we needed to install the RDS role. I did so, but now the application we are trying to share is running much slower than it was before. Prior to the role installation, it was taking about 5 seconds to open; now it is taking a few minutes to open -- without any other users logged on except me. My assumption is that the RDS role may be too much for this micro instance to handle, and currently, changing to another size instance is not an option (it may be possible later if we were to receive enough funding). This leads me to the following questions: 1) Is it a sensible assessment to assume that it is the RDS role is slowing things down, or are there other things that I could look at to speed it up? We are talking about a machine with ~600MB of memory. 2) If I revert back to the pre-RDS role, is there any legitimate way (in terms of purchasing RDS licenses) to get more than 2 concurrent desktops? I did read this, and am not questioning that the answerer is knowlegeable; but someone else may have some other experience. I am also making it clear that we want to do this in a legitimate way. Thanks in advance for any assistance that can be provided! EDIT: if it is helpful in answering the question, the application in question is a Lotus Approach database. Also, I am asking this from a technical perspective: not a legal one. I want to know if it is possible to install valid licenses without the RDS role.

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• Why am I experiencing random connection timeouts? (CentOS)

  - by Ryan

  I have a CentOS server setup that currently hosts several websites (all relative of each other in some form or another). As of recently throughout the day at the most random times the website speed will lag to a crawl and eventually hit a connection timeout. When I say random times this typically happens anywhere between 10am and 1pm usually, however, this morning this happened to me at 8am. I do not have a lot of familiarity with server knowledge as far as what I am looking for in this situation. What are some possible causes of why my server is slowing the websites down to a complete crawl or timing out? Are there specific things I should be checking for when this happens? I have noticed using: tail /var/log/httpd/access_log That usually when this down time occurs there are lot of IP addresses related to BingBot, Googlebot, and sometimes various bots or spiders that I am unfamiliar with. Could this be related and if so how can I avoid this from causing my websites to lag out? Thanks in advance for any help or advice. The websites that are timing out are built with PHP and use a MySQL database to display information.

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• Combine multiple rows into one

  - by Jim

  I am trying to combine multiple rows of data into one. Column A contains the value on which the groupings will be based -- rows whose Column A values match will be combined into one row. My range extends from column A through X so I need a matching row of data to start in column Y. Example: +--------------+ ¦ 1001 ¦ A ¦ C ¦ ¦ 1001 ¦ B ¦ D ¦ ¦ 1002 ¦ A ¦ E ¦ ¦ 1002 ¦ B ¦ F ¦ ¦ 1002 ¦ C ¦ G ¦ +--------------+ Desired Result: +------------------------------+ ¦ 1001 ¦ A ¦ C ¦ B ¦ D ¦ ¦ ¦ ¦ 1002 ¦ A ¦ E ¦ B ¦ F ¦ C ¦ G ¦ +------------------------------+ The VBA code I am currently using is not taking the entire contents of the matched row. It is only taking the data in the 2nd column and moving it up. VBA Code: Sub Mergeitems() Dim cl As Range Dim rw As Range Set rw = ActiveCell Do While rw <> "" ' for each row in data set ' find first empty cell on row Set cl = rw.Offset(0, 1) Do While cl <> "" Set cl = cl.Offset(0, 1) Loop ' if next row needs to be processed... Do While rw = rw.Offset(1, 0) cl = rw.Offset(1, 1) ' move the data Set cl = cl.Offset(0, 1) ' update pointer to next blank cell rw.Offset(1, 0).EntireRow.Delete xlShiftUp ' delete old data Loop ' next row Set rw = rw.Offset(1, 0) Loop End Sub

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• Ubuntu 10.04 network manager issues

  - by Shark

  I was using the default network manager to connect to my wi-fi network, but if the connection is dropped or router restarted the network manager wont reconnect automatically after i guess a couple of tries and just gives a pop-up to connect manually . To avoid this annoyance I installed WICD but though it does try to reconnect to the network after a drop in connection it is unable to resolve the ip address and i am left with an even bigger annoyance . 1. Is there a way to counter either of these issues ? 2. Something like a background process that will check network status periodically and then try to connect to a favored network ? Edit- out put of lshw -C network *-network description: Wireless interface product: Broadcom Corporation vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:12:00.0 logical name: eth1 version: 01 serial: c0:cb:38:18:9b:7f width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=wl0 driverversion=5.60.48.36 ip=192.168.11.2 latency=0 multicast=yes wireless=IEEE 802.11 resources: irq:17 memory:fbc00000-fbc03fff *-network description: Ethernet interface product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:13:00.0 logical name: eth0 version: 02 serial: f0:4d:a2:94:2d:74 size: 10MB/s capacity: 100MB/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half latency=0 link=no multicast=yes port=MII speed=10MB/s resources: irq:29 ioport:e000(size=256) memory:d0b10000-d0b10fff(prefetchable) memory:d0b00000-d0b0ffff(prefetchable) memory:fb200000-fb21ffff(prefetchable)

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• How to verify system using right GPU, after system reset [duplicate]

  - by Antoros

  This question already has an answer here: Is my mobile AMD card being used? 2 answers OS: Windows 8 CPU: Intel® Core™ i7 Processor 3635QM GPU 1 : Intel HD Graphics 4000 GPU 2 : AMD Radeon™ HD 8870M other info: System Spects Problem: im unsure that CCC is using AMD card instead of Intel's, i have encountered several issues since updating to 8.1 and i don't know what to do What happened: Installed 8.1 patch first day After 1 minute of use, BBSOD, windows never loaded again System restore wouldnt recognize 8.0 restore points i did a system reset to windows 8 since the laptop was only 3 weeks old System Broke, it did restore to factory BUT kept the registry almost intact, i had to install almost everything again, since the factory drivers where working with the updated one's registry and several problems CCC Broke too <- What i've already done Installing new drivers on top of old ones didnt work, so i used AMD uninstaller first Uninstalled and Re-installed Intel's HD Graphics Driver Tried to install mobile center, but AMD told me that it wasnt compatible (even if thats the only driver that they provide via their page as seen Here) Tried to use Auto-Detect, couldnt install driver because card was disabled because it didnt have the drivers... (see what they did here?) Had to use a workaround with Samsung Update, the driver didnt appear as download so had to use search and downloaded the driver manually. Now the graphic card appears on device manager and catalyst but as 8800 series (not exact model), and cant check the card with neither dxdiag/GPU-z/HWMonitor when right-clicking on CCC only Intel card appears launching a game and using as "high performance" would speed it up a little but i cant be sure How to verify its working properly? HWMonitor wont show AMD card even when set to high performance Latest GPU-Z wont work because a problem with Intel's, and legacy ones wont either what can I do now? I don't even know if I fixed my problem or not, and i also want to to use Adobe Premier with it, and its locked (the option to run it with the amd card not intels) Edit: now it seems to work, but cant change the setting for adobe Premiere and other programs that i Need to

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• Netgear CG3000D new Modem/Router - Random High Ping

  - by justin.chmura

  Cox just recently came out and looked at my internet and decided that the modem I had was causing high latency issue. The speed was fine but the ping would spike to around 100 and over when gaming or putting a load more than browsing on the line. After they replaced it, it seems like I get better latency, but when it spikes, I get upwards of over 300 ping with like 500 jitter. I figured I would hit the serverfault universe before sending another email to Cox. I opted not to do the Cox setup as it was an extra $20 which I thought would have just setup the wireless (which I can handle). Is it a setting or something that I missed that needs to be setup? The firmware for the CG3000D is awful and not fun to use. I did change some hidden settings on the RgServices.asp page (I'll attach a screenshot). I've also heard that the Router/Modem combos are awful and that I should go back and just ask for a modem stand-alone. Any input is helpful. All screenshots: http://imgur.com/a/JX6qu#0

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• Why does GIMP start up so slow on my machine?

  - by muntoo

  EDIT 2: One way would be to disable script-fu. Does anyone know how to disable it at startup? Is it possible? Would GIMP still work? What wouldn't work? Could I start it later, after loading? Is there any way to speed up GIMP's startup time on Windows Vista Home Premium 32-Bit 1.6 [Dual] Intel Processors? On XP [different computer], it loads in less than 3 seconds. On Vista, it takes 20 seconds: 2 Seconds (other - fonts, brushes, etc) 18 Seconds (extension-script-fu) It just freezes at extension-script-fu. Looking at Process Explorer, I see that it's not taking any CPU at all. EDIT 1: It does seem to be taking 50% of the CPU. It gets stuck for about 18 seconds, and then starts working again. Then, the actual GIMP program pops up [...finally]. I have the latest stable version running (I think). I tried it with XP SP2 Compatibiliy mode and/or Run As Administrator, but that didn't help.

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• PXELinux and compressed kernels/images

  - by Yvan JANSSENS

  Is it possible to boot compressed kernels with a compressed initrd with PXELinux? First, a little background: We created a custom Linux distro, for diskless OpenCL computing nodes. We want those nodes to fetch their OS from the network. Our Distro is composed out of a kernel (duh) and a large initrd which is loaded into RAM and everything is executed from there. We chose to run everything off the initrd for two reasons: NFS was not an option to serve the filesystem's extra contents Fast file access from RAM. No persistent storage needed, data and config is pulled dynamically through a SOAP service. Now our initrd is about 450M in size. At our network speeds, it takes about two to three minutes to load a single client. Will compression speed up te downloading, and if yes, which one should be used? Is LZMA supported by PXELinux, or do we need to stick to bzip2 or gzip? Because of the 2-3 minutes loading time, booting 15 nodes over the same network link takes quite a lot of time. We decided not to use hard drives or CD/DVD drives, for financial reasons (cheapest HDD @ €30 times 15 is a lot of money saved ;-) ) So, our question is: what compression options are available for this setup? And how do we do this? Thank you for your time! Yvan Janssens

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• What is the fall off of subsecond throughput on Ethernet Network Interfaces

  - by Kyle Brandt

  On a network interface, speeds are given in term of data over time, in particular, they are bits per second. However, in the uber-fast world of computing -- a second is kind of a really long time. So for example, given a linear falloff. A 1 GBit per second interface would do 500MBit per half second, 250Mbit per quarter second etc. I imagine at certain units of time, this is no longer linear. Perhaps this is set by ethernet frequencies, system clock speeds, interrupt timers etc. I am sure this varies depending on the system -- but does anyone have more information or whitepapers on this? One of the main reasons I am curious is to understand output drops on interfaces. Even if the speed per second is much lower than the interface can handle -- perhaps there are spikes that cause drops for only small numbers of milliseconds. Perhaps various coalescing would hide this effect -- or perhaps increase it on the receiving interface? Do queues make a difference here? Example: So given if this is linear down to the MS we would have 1Mbit/MS, and if Wireshark isn't distorting what I see, should I see drops when I have a spike beyond 1Mbit?

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• Is it a good Idea to switch to a SSD to use less battery?

  - by Walter Maier-Murdnelch

  I am thinking of buying a SSD for my laptop, mainly for the purpose of extended operating time when running on battery. At the moment I use a Hitachi HTS545032B9A300 (320GB) (Datasheet) as main drive and a Seagate Momentus 5400.3 120GB as secondary drive. I dualboot Windows and Linux but I don't need the windows partition any longer, a 120GB SDD would be more than sufficient space-wise. Speed is not an issue for me, I make heavy use of tmpfs (ramdrive) within Linux and transfers of bigger files are mainly through some network filesystem anyways, thus a cheaper SSD should do. For the purpose of comparison I chose the OCZ Vertex Plus 120GB. Power consumption always is a big promotional thing the industry uses to make me want to buy their SSDs, some sheet on the OCZ page provides an astonishing comparison of desktop HDDS and SSDs. The numbers I got comparing my laptop HDD and their SSD were not really astonishing any longer. Hitachi 320GB HDD: Startup (W, peak, max.) 4.5 Seek (W, avg.) 1.7 Read / Write (W, avg.) 1.4 Performance idle (W, avg.) 1.3 Active idle (W, avg.) 0.8 Low power idle (W, avg.) 0.5 Standby (W, avg.) 0.2 Sleep 0.1 OCZ 120GB SSD: 1.5W active 0.3W standby I see that there are differences, but actually they don't seem that high as I though they were. And compared to the power consuption of the rest of my system I wonder if it makes a difference at all. Have I just taken the wrong look at the whole thing or may I be better off to buy another battery for my laptop?

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• FreeBSD jail IMAP/MTA config recommendations

  - by kobame

  I've got access to my "own" FreeBSD jail. The jail has only basic, unconfigured system, but I have full access to FreeBSD ports, and (jail)root too. Now I need to setup my jail as IMAP/MTA. The question: What packages are EASIEST for config and later administration, (the simplest possible setup, with the minimum needed configuration) when: i haven't any preferences (don't know any yet) my (one) domain is managed by ISP, so don't need DNS need only IMAP for few users (up to 20 mailboxes) need secure transport layer (IMAPS/993) password auth, no LDAP, no kerberos, nor databases, nothing like fancy things... need easy-setup easy-admin MTA, with simplest possible password SMTP auth, (again no LDAP, nor DB), secure transport layer but would be nice have virus-scan and some anti-spam protection So, what ports I should install for MTA and IMAP? MTA (Sendmail, Postfix, Exim)? antivirus (ClamAV) antispam??? IMAP(S), (Dovecot, Courier) when the main criteria are: easy setup, and easy administration. When I googled I found only complicated setups for thousands of users with LDAP, databases and so on - too big-caliber for my small (easy?) needs. Any pointer to an easy howto is very welcomed.

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• sysbench memory test on ec2 small instance

  - by caribio

  I'm seeing a problem with sysbench memory test (the default version that's compiled in). This is on Ubuntu Maverick, sysbench installed via apt-get install sysbench. Running the same thing on Ubuntu @ Rackspace worked just as expected. While the CPU and I/O tests worked fine on EC2 servers, the memory test just runs without doing anything (notice the 0M in the test results). The instance used was the publicly available 'stock' Ubuntu image with no changes to it: ./ec2-run-instances ami-ccf405a5 --instance-type m1.small --region us-east-1 --key mykey Supplying more arguments (such as: --memory-block-size=1K --memory-total-size=102400M) didn't help. What am I doing wrong? Thanks. sysbench --num-threads=4 --test=memory run sysbench 0.4.12: multi-threaded system evaluation benchmark Running the test with following options: Number of threads: 4 Doing memory operations speed test Memory block size: 1K Memory transfer size: 0M Memory operations type: write Memory scope type: global Threads started! Done. Operations performed: 0 ( 0.00 ops/sec) 0.00 MB transferred (0.00 MB/sec) Test execution summary: total time: 0.0003s total number of events: 0 total time taken by event execution: 0.0000 per-request statistics: min: 18446744073709.55ms avg: 0.00ms max: 0.00ms Threads fairness: events (avg/stddev): 0.0000/0.00 execution time (avg/stddev): 0.0000/0.00

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• Servers/Websites Keep Going Down

  - by Tyler Johnson

  Okay, I'm a noobie. I know how to build and compose a website, but I have no idea what I'm doing when it comes to servers and server commands, etc. I've recently had a problem with all of my sites on our servers going down all at once and then I have to go in and reboot the server for them to come up again. At first this was annoying, but now it is becoming agonizing as it now takes 3-4 reboots for the websites to come back up. I contacted support for my hosting, but they are not being very helpful. They just keep telling me what the issue might be and basically telling me that I'm going to have to look into it and figure it out, which really isn't possible since I know nothing. Anyway, here are the things they said were possible reasons: They said I have "strange logs" in my Apache webserver log, error: sh: fetch: command not found. My php.ini memory limit is: 256M which is very high. It should be 32M or 64M. Server is reaching Max Clients, meaning we have more than 150 visitors at a time. (They supposedly "fixed" this, but the sites/server are still going down) I have some Wordpress sites with plugins getting errors like: PHP Warning: pack(): Type H: illegal hex digit G in... PHP Fatal error: Cannot use object of type stdClass as array in... PHP Fatal error: Maximum execution time of 30 seconds exceeded in... PHP Fatal error: Call to undefined function file_exists() in... PHP Parse error: syntax error, unexpected '<' I know that's a lot, but I really am at wits end and have no idea what to do now. If anyone could maybe give me some advice or point me in the right direction I would greatly appreciate it! Thanks! Oh, and here are the specs for my server: RAM: 2048MB CPU Shares: 40 Primary Disk: 50GB Data Transfer: 75GB Port Speed: 5Mbps Type: Linux

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• VPS goes slow at more than 20 users online at the same time

  - by hachiari

  I have 512 MB VPS (brustable to 1GB) Somehow, the site goes slow when there are about 10 users, and becomes impossible to load at 20 users online at the same time. I wonder what could be the problem for this. The bandwidth connection of the VPS is 1Gbps. Here is some settings in my VPS: KeepAlive Off <IfModule prefork.c> StartServers 7 MinSpareServers 7 MaxSpareServers 10 ServerLimit 64 MaxClients 64 MaxRequestsPerChild 0 </IfModule> my.cnf settings - calculated Max Memory 300MB Output from UNIXBENCH INDEX VALUES TEST BASELINE RESULT INDEX Dhrystone 2 using register variables 376783.7 13429727.4 356.4 Double-Precision Whetstone 83.1 1137.5 136.9 Execl Throughput 188.3 1637.4 87.0 File Copy 1024 bufsize 2000 maxblocks 2672.0 148868.0 557.1 File Copy 256 bufsize 500 maxblocks 1077.0 79430.0 737.5 File Read 4096 bufsize 8000 maxblocks 15382.0 1410009.0 916.7 Pipe Throughput 111814.6 4419722.0 395.3 Pipe-based Context Switching 15448.6 561505.1 363.5 Process Creation 569.3 10272.7 180.4 Shell Scripts (8 concurrent) 44.8 514.3 114.8 System Call Overhead 114433.5 3537373.8 309.1 ========= FINAL SCORE 295.0 I am afraid that the VPS company limit the number of connection to the VPS... is it possible? The server is in Japan, but the site has global traffic (some of the traffic are from countries with low speed connection). Could this be the problem? This is a serious problem :( my site just cant grow if this keeps on happening... please tell me if you have any idea. Thank You, Bryant

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• Apache2: Limit simultaneous requests & throttle bandwidth per IP/client?

  - by xentek

  I want to limit simultaneous requests & throttle bandwidth per IP/Client on a single apache vhost. In other words, I want to ensure that this site, which hosts large media files, doesn't get hammered by someone trying to download everything all at once (just happened the other night). I'd like to limit the outgoing transfer speed overall for this site, as well as limit the number of connections a single IP can make to the server to a sane default (i.e. within normal browser limits for multiple requests so page loads aren't effected too much). Bonus points if I can actually scope it to file types (i.e. leave web files alone, but apply these rules to just the media files). We're running Ubuntu 9.04 on all the servers, and have two apache/php servers being load balanced via Round Robin by a squid proxy server. MySQL is running on its own box as well. We've got plenty of bandwidth to give them, so I don't really want overall caps, but just want to throttle the amount of memory/CPU it takes to serve this site. There other sites on these servers that we don't want to apply these rules too, just want to keep this one from hogging all the resources. Let me know if you need more info! Thanks in advance for your suggestions!

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