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  • Connecting to unsecured wireless network

    - by Sanchez
    I would like to know what information is public and can be intercepted in a non-open, but unsecured wireless network. Moreover, is there anything I can do to make it more "secure", other than using https connection whenever possible. In more details, I recently discovered (with surprise) that the wireless network in my school is actually unsecured. Although not everyone can connect to it (you need a student ID), I am told that certain softwares like Wireshark would be able to intercept the data. Since I have been using the network for all private purposes (email, facebook etc), I do feel quite insecure now and would like to understand the situation a bit better. I installed Wireshark and tried to play with it but all I can see are something alien to me. In any case, all I see seems to come directly/indirectly from my IP address, and I have long thought that usually different computers in the same wireless network would be assigned different addresses. Am I wrong? If not, then I feel very confused about what information is actually being captured (potentially by other users in the network, since I don't think I could capture activities of others in the same network anyway), and whether it's safe to use the network at all. (Gambling on others in the same network showing good behaviour is apparently not an option.) Thank you.

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  • How do I prevent a tar pipe from causing swapping?

    - by Jeff Shattock
    I have a rather large filesystem that I need to transfer from one Linux server to another. I figured the best way to do this was via a tar/netcat pipe arrangment, something like tar c . | pv | nc blah blah blah And it works great, the network stays fairly saturated, life is good. Until the source machine starts swapping. The files are on a raid on the source system, so the read speed is much faster than the write speed on the other end. Since the dest machine hasnt picked up the data yet, the source machine needs to stick it somewhere, so into RAM it goes, until there is no more free RAM. It then starts swapping, which is horribly painful since that machine has its OS installed on a somewhat slow CF card. Both machines have 4GB of physical ram, 64 bit Ubuntu 9.04 server. GigE link between them. How do I prevent this swapping? Can I put a "speed-limit" on the tar or netcat process so that the transfer speed doesn't overwhelm the write throughput on the destination end? The man pages didn't list anything, but there might be something I'm overlooking.

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  • Forcing programs to be installed to another drive

    - by zyboxenterprises
    I have an SSD as my main Windows drive, with a 640GB 2.5" HDD, partitioned to store programs and user settings, and also to act as backup (it's the only thing I had lying around at the time of building my PC). The task was to make the PC as fast as possible, while having an increased storage capacity available to store normal user data, and to assist in my small data recovery business. The problem is that whenever I install a program, it installs to C:\Program Files [(x86 for the 32 bit programs]\, although I have changed the environment variables. This wouldn't normally be an issue, however every installation program points its shortcut to my 640GB HDD. The root layout of both drives: To clarify: Program files get installed to C:\ Program shortcuts are always pointed to Z:\, my 640GB HDD Modifying the relevant environment variables doesn't do anything, I looked at this, but however it only talks about modifying the registry and environment variables, which I have already done so. I install to the Z:\ drive if the installation program lets me change the installation path, but however the installation programs sometimes don't let me change this. Is there a way that I can force every program to install to the relevant location on Z:\? Perhaps I'm missing something here? Edit: Found this program; would it be appropriate to use in my case? I would be able to move the entire Program Files (and its x86 version) to Z:\, without impacting on the performance.

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  • Did I miss anything when checking for passwords? [migrated]

    - by Keltari
    There's a bit of a story to this, so bear with me... I am looking for a new job and came across a posting for a computer forensics position. Its not really my field, but I thought I would apply anyway, just for fun. To make a longer story shorter, they want you to uncover as many passwords as you can find. I downloaded an image and dd'd it to a thumbdrive. The only thing visible was a text file, which contained a password. I knew there had to be more, so I used an undelete utility and found 2 deleted files. First there was another text file with a password - easy. The other was a .pst file which I mounted into outlook. There were some emails with passwords, as well as an email with an image. Another email has a link to a stegenography site. Obviously, there was a file hidden in the image, so I went to the website and downloaded the stegenography decoder. I had to try some of the passwords I had found to get the file to decrypt, and sure enough, there was another text file with a password. I called it a day at that point. Did I miss any other methods?

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  • Nginx terminate SSL for wordpress

    - by Mike
    I have a bit of a problem. We run a wordpress blog behind a ngnix proxy and looking to terminate the ssl on the nginx side. Our current nginx config is upstream admin_nossl { server 192.168.100.36:80; } server { listen 192.168.71.178:443; server_name host.domain.com; ssl on; ssl_certificate /etc/nginx/wild.domain.com.crt; ssl_certificate_key /etc/nginx/wild.domain.com.key; ssl_session_timeout 5m; ssl_protocols SSLv2 SSLv3 TLSv1; ssl_prefer_server_ciphers on; ssl_session_cache shared:SSL:10m; ssl_ciphers RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP; location / { proxy_read_timeout 2000; proxy_next_upstream error; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; proxy_max_temp_file_size 0; proxy_pass http://admin_nossl; break; It just does not seem to work. If I can hit https://host.domain.com but it quickly switches back to non-secured from what I can see. Any pointers?

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  • Copying files between linux machines with strong authentication but without encryption

    - by Zizzencs
    I'm looking for a suitable program to copy files from one linux machine to another one. The program should be able to do authentication but it should not do encryption. The reason behind the latter is the lack of CPU power to do the encryption. I copy backups from ~70 machines to a single backup server simultaneously. The single server is an HP Proliant DL360 G7, with 10 Gbps ethernet connection and an FC storage backend that can do 4 Gbps. Through FTP I can write ~400MB/sec to the storage (that's about what I want) but through ssh with arcfour I can only do ~100MB/sec while having 100% CPU usage. That's why I want file transfers not to be encrypted. The alternatives that I found not really suitable: rcp: no authentication, forget it FTP: making the authentication "secure" (at least preventing plain-text password exchange) is possible but not really easy and I haven't found a method to force any FTP daemon to encrypt the control channel (for the authentication) and not to encrypt the data channel (for data transfers) SCP/SFTP: in farely recent ssh(d) implementations you can't turn off encryption. The best you can do is to use the arcfour cypher for the encryption but it sill uses too much CPU power for my needs. rsync over ssh: same problems as with SCP/SFTP. plain rsync: from the documentation of rsyncd: "The authentication protocol used in rsync is a 128 bit MD4 based challenge response system. This is fairly weak protection, though (with at least one brute-force hash-finding algorithm publicly available), so if you want really top-quality security, then I recommend that you run rsync over ssh." It's a no-go. Is there a protocol/program that can do exactly what I want? (A big plus would be if it could work on windows as well and/or if it would support rsync-stlye copying/synchronization (e.g. copy only the differences).)

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  • Nginx + WordPress + HHVM: Why isn't Batcache working? Would Varnish help even more?

    - by javipas
    I've heard great things about HHVM, so I've setup a copy of WordPress blog (on another domain) with Nginx (with the Pagespeed module) and HHVM. Right now the benefits are obvious: on the same config, load times are between two and three times faster. I'm trying to speed up things a little bit, and I've also installed Memcached and Batcache. I've installed the memcached package, copied object-cache.php (Pastebin) onto the root folder of the WordPress blog, and after that I've installed the Batcache plugin and copied the advanced-cache.php (Pastebin) file onto the wp-content folder. Also, I've included the line define('WP_CACHE', true); in the wp-config.php file. It seems it doesn't work, though. If I quickly reload the page several times Batcache should show the cached page, but it doesn't. It's easy to check that by reloading (Cmd+R on Chrome on OS X) the page several times and then viewing the page's code. Under the <head> section I should see some batcache stats, but they aren't there. I wonder if someone could give me some hint on this. On a side note, I don't know if I could add some other component in order to help the performance be even better. I'm thing about Varnish, but I'm not sure if it's just useless and it's just another way to the same I'm currently doing. Any other component there? (I'll test CDN for images, minifying js, etc and some other tricks as well, but I'm talking from the server perspective).

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  • MySQL (local) owner and permissions

    - by Steve Nelson
    I asked this question on the MySQL forums and got no answer. I asked on StackOverflow and received a recommendation to try on ServerFault. So here I am. I recently successfully installed the 64 bit version of mysql-5.5.8 on a MacBook Pro in the /usr/local directory. To address a completely unrelated software (RVM actually) , I chown-ed my /usr/local directory to $USER, Which made MySQL very unhappy. It complained specifically about the /usr/local/mysql/data directory, so I chown-ed that directory to _mysql:wheel. Everything appears to work again, but it made me wonder if I would have been better off changing the owner of the whole /usr/local/mysql directory, not just the data subdirectory. Since I neglected to make notes of what owner the default installation runs under before rashly changing the owner of the /usr/local directory, could someone tell me what owner and permissions the /usr/local/mysql directory is by default if you don't inadvertently screw it up? :-/ In terms of permissions I'm guessing rwxr-xr-x would be appropriate (that's what the data directory currently has and it appears to be working fine), but reinforcement for that hunch would be appreciated. Thanks for any help. Steve

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  • Looking for ballpark pricing on an affordable a Cisco VOIP solution for our office

    - by guytech
    We have about 8 incoming PSTN lines that are currently on an old and antiquated Nortel Meridian ICS system. This system has been giving us some grief. We're looking for a new VOIP solution. I've been looking at a Cisco solution and it does seem pricey but I'm sure effective. Unfortunately, we probably can't afford a Cisco Unified Communications 520 which seems to be the ideal solution. We have about 15 people who need an extension and voicemail. We really don't have any need for a fancy system just an auto attendant of some sort when people call us. It looks like we'll have to get an older router and an addon card for what we're looking for to get best value pricing. However, I don't know a a lot about Cisco voice products so I'm a bit lost as to what to get. The only thing I am sure on is the pricing on VOIP phones which we expect to be about ~$100-200. However, I'm not sure what pieces of VOIP infrastructure to get. Any advice? I am familiar with Asterisk but right now I'm looking on pricing concerning a Cisco solution.

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  • Java Deployment and Configuration (1.6.0_21)

    - by user125137
    Sofware: Java Runtime Environment 1.6.0_21 OS: Windows XP Professional 32-Bit, SP3 Situation: a new piece of web based software is being deployed this week and prior to this all the company desktops need to be set up to meet the requirements of this software. One of these requirements is JRE 1.6.0_21. I have successfully scripted the removal of all other Java versions and the installation of the required version, however I cannot get it configured properly. One of the requirements is that the Java console be set to disabled - if it is not it can cause an issue with a particular function. I have pushed out a deployment.config and deployment.properties but the console just will not disable itself.. I know the config is being read correctly because the update tab is being correctly disabled and removed. deployment.config: deployment.system.config=file\:C\:/WINDOWS/Sun/Java/Deployment/deployment.properties deployment.system.config.mandatory=true deployment.properties: #deployment.properties #Fri Jun 15 09:34:31 EST 2012 deployment.version=6.0 deployment.console.startup.mode=DISABLE deployment.javaws.autodownload=NEVER deployment.javaws.autodownload.locked= There is no change if I set the console to ENABLE either - it remains on the default of hidden. I'm sure I can disable the console with a registry change of some form but my preference is to have it done via the deployment files as it gives the option of centralising the properties file to a network share if we wish. If anyone has any suggestions it would be appreciated.

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  • Finding default gateway in an openvpn environment in windows

    - by Alexander Trümper
    I need to find the default gateway in a openvpn scenario where the route output looks like that: IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 10.49.73.1 10.49.73.24 10 0.0.0.0 128.0.0.0 10.8.0.1 10.8.0.2 30 So I googled around a bit and a found this script here: @For /f "tokens=3" %%* in ( 'route.exe print ^|findstr "\<0.0.0.0\>"' ) Do @Set "DefaultGateway=%%*" echo %DefaultGateway% This works, but matches both lines in the route output. But I need to find this line: 0.0.0.0 0.0.0.0 10.49.73.1 10.49.73.24 10 So I tried to modify the findstr parameter like this: findstr "\<0.0.0.0\>.\<0.0.0.0\>" in the expectation that '.' will match for the tab between the columns. But it doesn't. It will still set DefaultGateway to 10.8.0.1 I couldn't find a clue in MS documentation either. Maybe someone knows the right expression? Thanks a lot.

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  • vSphere - datastore falling off a host

    - by Chadddada
    Recently we have been running the vCheck powershell script daily in order to help in monitoring our vSphere ESX 4.0 environment. One of the oddities that we have been seeing is that some of the datastores on the SAN don't always show up on every host. Our hosts are connected redundantly, via FC, to some brocade FC switches, which then connect via fiber to our EMC Ax4 SAN. While all the datastores are presented to each host we have, and they see them initially, they sometimes seem to fall off and are no longer visible. It easy enough to rescan for datastores and add them back to the hosts the hosts but this seems to be an error. Has anyone else seen this or know why it may be happening? Responses to questions: 1. Is it always the same ESX servers that lose their connection? – Scott Warren No this happens randomly on random hosts. If a VM is running on a particular host, of which the VM's disks are on a SAN datastore, then that datastore won't disappear. It seems to happen if a host doesn't touch a datastore for a bit and it just forgets about it.

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  • Large, high performance object or key/value store for HTTP serving on Linux

    - by Tommy
    I have a service that serves images to end users at a very high rate using plain HTTP. The images vary between 4 and 64kbytes, and there are 1.300.000.000 of them in total. The dataset is about 30TiB in size and changes (new objects, updates, deletes) make out less than 1% of the requests. The number of requests pr. second vary from 240 to 9000 and is dispersed pretty much all over, with few objects being especially "hot". As of now, these images are files on a ext3 filesystem distributed read only across a large amount of mid range servers. This poses several problems: Using a fileysystem is very inefficient since the metadata size is large, the inode/dentry cache is volatile on linux and some daemons tend to stat()/readdir() it's way through the directory structure, which in my case becomes very expensive. Updating the dataset is very time consuming and requires remounting between set A and B. The only reasonable handling is operating on the block device for backup, copying, etc. What I would like is a deamon that: speaks HTTP (get, put, delete and perhaps update) stores data it in an efficient structure. The index should remain in memory, and considering the amount of objects, the overhead must be small. The software should be able to handle massive connections with slow (if any) time needed to ramp up. Index should be read in memory at startup. Statistics would be nice, but not mandatory. I have experimented a bit with riak, redis, mongodb, kyoto and varnish with persistent storage, but I haven't had the chance to dig in really deep yet.

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  • Windows 7 starts getting sluggish over a few days

    - by munrobasher
    Myself and the other developer are running Windows 7 Enterprise 64 bit with 8GB RAM on different Gigabyte motherboards with Quad core Intel CPUs. Most of the time, it runs like a dream. We use VMware workstation a lot (hence the 8GB) and that works well. Except... now and then, after the PCs have been on for a few days, the whole system starts getting really sluggish doing certain tasks. The other's developer's system is far worse than mine with it taking up to a minute to launch IE. Today, mine has gone sluggish but nowhere near as bad. For example, normally when I click on a new tab in IE, it's instant. Today, there's an obvious delay. Right-clicking in this window to trigger iSpell is normally instant, right now it takes about five seconds. I've got resource monitor open on my second monitor and when I did that right-click, there was no obvious peak in CPU, disk or memory. A reboot does fix it so it does sound like a resource issue but haven't a clue what might be to blame. The two computers have similarities (same spec) but also differences (like motherboard, RAM & CPU models). So I guess the question is, any pointers on diagnosing why a PC is sluggish? What could cause such a right-click slow down in IE for example? It sounds like such a simple operation. NOTE: whilst typing this message alone, it was fine performance wise. I can click around the page no problem but right-click still is noticeable slow. Will reboot over lunch... Cheers, Rob.

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  • What methods are available for updating a non-Internet-connected VMWare ESXi host?

    - by romandas
    I have a stand-alone installation of VMWare vSphere Essentials, with a vCenter Server and 3 ESXi 4.0 host servers. The environment is intended to remain as a stand-alone network, with the exception that I can "float" a workstation or server between the 'Net and the VMWare network for patches and maintenance. With other installations, where the Internet is available, I've used the vSphere Host Update utility to connect to VMWare and then apply the patches to the ESXi hosts. My problem is that this utility does not seem to function if it cannot connect to both VMWare and the ESXi host at the same time, as the scan for patches function will not scan the server without connecting to VMWare's site to sync its repository first. Even if I sync it, disconnect from the 'Net and connect to the VMWare network, it still won't scan hosts for required patches -- it will prompt for syncing with VMWare and if you click No to syncing, the scan does not occur. Does anyone know of other options for updating the ESXi hosts in some automated fashion? I believe I can manually pull down required patches and apply them, but this will not scale well, and in the future I'm sure I'll want something a bit more scalable.

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  • How can I install iTunes in such a way that it can't put any "hooks" or helper programs on my computer?

    - by Joshua Carmody
    I'm buying a new iPad, which means I must once again install iTunes. I've not used iTunes in more than 6 months, since I bought a new computer. I don't like iTunes, but I can live with using it to buy/manage media and sync my Apple devices when the program is open. What I would like to do though, is find a way to install iTunes in such a way that it has absolutely no effect on my system when it is closed. iTunes normally installs several helper programs such as iTunesHelper.exe, and the Bonjour service. These programs run in the background when iTunes is closed. You can force-close them, or remove them from your setup files, but iTunes will often put them right back when you run it. I know these programs are mostly harmless, but they have at times caused issues such as iTunes spending system resources trying to catalog media files or drives connected to VPN, or other issues. At best they're just one more small background process eating up a small piece of my CPU time and RAM. How can I run iTunes without letting it get it's "hooks" into my system? One thought I had is that I could create a Windows user account just for iTunes, and deny it admin privileges. Then if I installed iTunes using that account maybe anything it installed wouldn't affect the "main" account on my PC? But I'm not sure if that would work.... Failing that, maybe some kind of virtualization software or sandbox I could install it in? I'm open to any suggestions. My system is an Intel-based PC running Windows 7 Professional 64-bit. Thanks!

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  • Wired to wireless bridge in Linux

    - by adrianmcmenamin
    I am attempting to set up my Raspberry Pi as a bridge (but I think this is not a question specific to the hardware) - using Debian wheezy. I have a hostapd.conf: (some details changed for security)... interface=wlan0 bridge=br0 driver=nl80211 auth_algs=1 macaddr_acl=0 ignore_broadcast_ssid=0 logger_syslog=-1 logger_syslog_level=0 hw_mode=g ssid=MY_SSID channel=11 wep_default_key=0 wep_key0=MY_KEY wpa=0 (yes, I know WEP is no good) And this in /etc/network/interfaces auto lo iface lo inet loopback iface eth0 inet dhcp allow-hotplug wlan0 iface wlan0 inet manual wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf iface default inet dhcp auto br0 iface br0 inet dhcp bridge-ports eth0 wlan0 Everything seems to come up ok, but I cannot associate with the bridged wireless connection - even though the flashing lights on the USB stick suggest packets are being exchanged. I have read somewhere that not all cards/devices will run in hostap mode - they won't pass packets in one direction: is that right? (The info was a bit old)- this my card: [ 3.663245] usb 1-1.3.1: new high-speed USB device number 5 using dwc_otg [ 3.794187] usb 1-1.3.1: New USB device found, idVendor=0cf3, idProduct=9271 [ 3.804321] usb 1-1.3.1: New USB device strings: Mfr=16, Product=32, SerialNumber=48 [ 3.816994] usb 1-1.3.1: Product: USB2.0 WLAN [ 3.823790] usb 1-1.3.1: Manufacturer: ATHEROS [ 3.830645] usb 1-1.3.1: SerialNumber: 12345 So, what have I got wrong here?

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  • Windows 7 access denied to executables.. by what?

    - by stijn
    Ever since I started using Windows 7 this problem has been bothering me. From time to time I see similar questions popping up on misc forums, but never did I see an answer. Here are two scenarios that nearly always reproduce it: the explorer way with explorer, navigate to a directory containing at least one exe file go one directory up immediately delete the directory just navigated to yields Folder Acces Denied dialog stating You need permission to perform this action You require permission from Administrators to make changes to this folder, with the buttons try Again and Cancel hitting Try Again never works immediately. Waiting a minute or so and then clickig it again does work note: if in step 2 and waiting a minute or more before going up one directory, the problem does not occur and the folder can be deleted the visual studio way build a project producing an exe file run the executable then close it immediately build the project again (by changing a single character in a source file for example) yields fatal error LNK1168: cannot open /path/to/the.exe for writing note: if in step 2 and waiting a minute or more before building again, the problem does not occur some specs happens both on Windows 7 32 and 64 bit, with VS2008/2010/2011 happens on 3 different machines I do not have a virusscanner of any kind I do have a bunch of services disabled, but nothing that prevents Windows from running normally, UAC is disabled as well happens on any type of disc I always use a user account that is in the Administrators group Obviously both scenarios are very similar and extremely reproducable. So I figured some process must have the file open for some reason, and release it again later. However, using systinternal's handle -a the exe file in question never shows up. (that is the correct way to use handle, right?) So while explorer/VS are reporting they cannot access the file, handle.exe says it's not in use anywhere. This leaves me rather clueless, so I'm wondering if someone can come up with a solution: why does this happen, and how to solve it?

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  • Apache2 default vhost in alphabetical order or override with _default_ vhost?

    - by benbradley
    I've got multiple named vhosts on an Apache web server (CentOS 5, Apache 2.2.3). Each vhost has their own config file in /etc/httpd/vhosts.d and these vhost config files are included from the main httpd conf with... Include vhosts.d/*.conf Here's an example of one of the vhost confs... NameVirtualHost *:80 <VirtualHost *:80> ServerName www.domain.biz ServerAlias domain.biz www.domain.biz DocumentRoot /var/www/www.domain.biz <Directory /var/www/www.domain.biz> Options +FollowSymLinks Order Allow,Deny Allow from all </Directory> CustomLog /var/log/httpd/www.domain.biz_access.log combined ErrorLog /var/log/httpd/www.domain.biz_error.log </VirtualHost> Now I when anyone tries to access the server directly by using the public IP address, they get the first vhost specified in the aggregated config (so in my case it's alphabetical order from the vhosts.d directory). Anyone accessing the server directly by IP address, I'd like them to just get an 403 or a 404. I've discovered several ways to set a default/catch-all vhost and some conflicting opinions. I could create a new vhost conf in vhosts.d called 000aaadefault.conf or something but that feels a bit nasty. I could have a <VirtualHost> block in my main httpd.conf before the vhosts.d directory is included. I could just specify a DocumentRoot in my main httpd.conf What about specifying a default vhost in httpd.conf with _default_ http://httpd.apache.org/docs/2.2/vhosts/examples.html#default Would having a <VirtualHost _default_:*> block in my httpd.conf before I Include vhosts.d/*.conf be the best way for a catch-all?

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  • Slow connection to Linux MySQL from Windows only (XAMPP)

    - by Josh
    I'm having a problem with a PHP project (using Kohana 3.2 framework) on my Windows 7 64-bit machine connecting to the database. The development database is stored on a Ubuntu Linux server on the local network. Other development machines running OSX and Linux are connecting fine. There are no other Windows development machines to test with. I can access MySQL fine using MySQL Workbench, and other projects (which I believe to be less database heavy) run mostly ok, only occasionally getting timeout messages. I'm constantly getting Maximum execution time of 30 seconds exceeded when functions such as mysql_query() are run in this particular project. Specifically, the Kohana file where the timeout occurs is MODPATH\database\classes\kohana\database\mysql.php [ 186 ]. My local set-up is: Windows 7 Professional 64bit XAMPP 1.7.7 (PHP 5.3.8) The output of uname -a of the Linux server is: Linux peach 2.6.38-11-server #50-Ubuntu SMP Mon Sep 12 21:34:27 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux I've tried the following, with no success: Disabling Windows firewall Switching between using a persistant and normal connection In my.cnf, adding skip-name-resolve Increasing wait_timeout Enabling bind-address I've run out of ideas now, and have no idea how to debug an odd issue like this. Has anyone come across this before, or have any idea how I could find the root of the issue, or what might be the problem?

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  • What is the best private cloud storage setup

    - by vdrmrt
    I need to create a private cloud and I'm searching for the best setup. These are my 2 most important requirements 1. Disk and system redundant 2. Price / GB as low as possible The system is going to be used as backup setup which will receive data 24/7 over SFTP and rsync. High throughput is not that important. I'm planning to use glusterfs and consumer grade 4TB hard-drives. I have worked out 3 possible setups 3 servers with 11 4TB HDD Setup up a replica 3 glusterfs and setup each hard drive as a separate ext4 brick. Total capacity: 44TB HDD / TB ratio of 0.75 (33HDD / 44TB) 2 servers with 11 4TB HDD The 11 hard-drives are combined in a RAIDZ3 ZFS storage pool. With a replica 2 gluster setup. Total capacity: 32TB (+ zfs compression) HDD / TB ratio of 0.68 (22HDD / 32TB) 3 servers with 11 4TB consumer hard-drives Setup up a replica 3 glusterfs and setup each hard-drive as a separate zfs storage pool and export each pool as a brick. Total capacity: 32TB (+ zfs compression) HDD / TB ratio of 0.68 (22HDD / 32TB) (Cheapest) My remarks and concerns: If a hard drive fails which setup will recover the quickest? In my opinion setup 1 and 3 because there only the contents of 1 hard-drive needs to be copied over the network. Instead of setup 2 were the hard-drive needs te be reconstructed by reading the parity of all the other harddrives in the system. Will a zfs pool on 1 harddrive give me extra protection against for example bit rot? With setup 1 and 3 I can loose 2 systems and still be up and running with setup 2 I can only loose 1 system. When I use ZFS I can enable compression which will give me some extra storage.

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  • Software RAID 1 Configuration

    - by Corve
    I have created a software RAID 1 quite some while ago and it always seemed to work for me. However I am not completely sure that I have configured everything right and do not have the experience to check so I would be very grateful for some advice or just verification that all seems right so far. I am using Linux Fedora 20 (32 bit with plans to upgrade to 64bit) The RAID 1 should consist of two 1TB SATA hard drives. This is the output of mdadm --detail /dev/md0 /dev/md0: Version : 1.2 Creation Time : Sun Jan 29 11:25:18 2012 Raid Level : raid1 Array Size : 976761424 (931.51 GiB 1000.20 GB) Used Dev Size : 976761424 (931.51 GiB 1000.20 GB) Raid Devices : 2 Total Devices : 1 Persistence : Superblock is persistent Update Time : Sat Jun 7 10:38:09 2014 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 Name : argo:0 (local to host argo) UUID : 1596d0a1:5806e590:c56d0b27:765e3220 Events : 996387 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 0 1 active sync /dev/sda The RAID is mounted successfully: friedrich@argo:~ ? sudo mount -l | grep md0 /dev/md0 on /mnt/raid type ext4 (rw,relatime,data=ordered) Basically my question are: Why do I only have 1 active device? What does the State removed at bottom mean? Also I noticed some strange error messages that I see on the console on system start and shutdown and always repeating in the background when I switch with Ctrl + Alt + F2: ... ata2: irq_stat 0x00000040 connection status changed ata2: SError: { CommWake DevExch } ata2: COMRESET failed (errno=-32) ata2: exception Emask 0x10 SAct 0x0 SErr 0x4040000 action 0xe frozen ata2: irq_stat 0x00000040 connection status changed ata2: SError: { CommWake DevExch } ata2: exception Emask 0x10 SAct 0x0 SErr 0x4040000 action 0xe frozen ... Are these errors related to the RAID? Something seems wrong with the SATA devices.. All together the system works (I can read and write to the mounted raid) but I always had these strange errors on startup shutdown (probably always in the background). Thx for your help

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  • tc u32 --- how to match L2 protocols in recent kernels?

    - by brownian
    I have a nice shaper, with hashed filtering, built at a linux bridge. In short, br0 connects external and internal physical interfaces, VLAN tagged packets are bridged "transparently" (I mean, no VLAN interfaces are there). Now, different kernels do it differently. I can be wrong with exact kernel verions ranges, please forgive me. Thanks. 2.6.26 So, in debian, 2.6.26 and up (up to 2.6.32, I believe) --- this works: tc filter add dev internal protocol 802.1q parent 1:0 prio 100 \ u32 ht 1:64 match ip dst 192.168.1.100 flowid 1:200 Here, "kernel" matches two bytes in "protocol" field with 0x8100, but counts the beginning of ip packet as a "zero position" (sorry for my English, if I'm a bit unclear). 2.6.32 Again, in debian (I've not built vanilla kernel), 2.6.32-5 --- this works: tc filter add dev internal protocol 802.1q parent 1:0 prio 100 \ u32 ht 1:64 match ip dst 192.168.1.100 at 20 flowid 1:200 Here, "kernel" matches the same for protocol, but counts offset from the beginning of this protocol's header --- I have to add 4 bytes to offset (20, not 16 for dst address). It's ok, seems more logical, as for me. 3.2.11, the latest stable now This works --- as if there is no 802.1q tag at all: tc filter add dev internal protocol ip parent 1:0 prio 100 \ u32 ht 1:64 match ip dst 192.168.1.100 flowid 1:200 The problem is that I couldn't find a way to match 802.1q tag so far. Matching 802.1q tag at past I could do this before as follows: tc filter add dev internal protocol 802.1q parent 1:0 prio 100 \ u32 match u16 0x0ed8 0x0fff at -4 flowid 1:300 Now I'm unable to match 802.1q tag with at 0, at -2, at -4, at -6 or like that. The main issue that I have zero hits count --- this filter is not being checked at all, "wrong protocol", in other words. Please, anyone, help me :-) Thanks!

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  • Can't mount Linux usd 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).

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  • Why can't I get out of display mirror mode?

    - by Roy Smith
    I've been running Ubuntu (10.04.1 LTS, 64-bit) for a while and just replaced my hardware with a faster machine with an ATI Radeon HD 5700 video card. I've got twin 1920 x 1080 displays. I downloaded the latest driver (ati-driver-installer-10-9-x86.x86_64.run) from the ATI web site and installed that. I've gone through a few rounds of playing with /etc/X11/xorg.conf, and can't get things right. At the moment, it's in display mirroring mode, and I can't figure out how to get it out of mirror mode. If I run Monitor Preferences, there's a "Same image in all monitors" checkbox. If I uncheck that, the little preview window switches to show two monitors. When I click Apply, it asks me to log out and log back in again. When I do that, I'm right back to mirrored mode. What's really weird is that I'm currently running a copy of xorg.conf from a coworker's machine. He's got identical hardware, and his display works fine. So, I'm inclined to think there's something else going on other than the conf file. Any ideas what might be wrong?

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