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  • Why is numpy c extension slow?

    - by Bitwise
    I am working on large numpy arrays, and some native numpy operations are too slow for my needs (for example simple operations such as "bitwise" A&B). I started looking into writing C extensions to try and improve performance. As a test case, I tried the example given here, implementing a simple trace calculation. I was able to get it to work, but was surprised by the performance: for a (1000,1000) numpy array, numpy.trace() was about 1000 times faster than the C extension! This happens whether I run it once or many times. Is this expected? Is the C extension overhead that bad? Any ideas how to speed things up?

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  • Does the order of the columns in a SELECT statement make a difference?

    - by Frank Computer
    This question was inspired by a previous question posted on SO, "Does the order of the WHERE clause make a differnece?". Would it improve a SELECT statement's performance if the the columns used in the WHERE section are placed at the begining of the SELECT statement? example: SELECT customer.id, transaction.id, transaction.efective_date, transaction.a, [...] FROM customer, transaction WHERE customer.id = transaction.id; I do know that limiting the list of columns to only the needed ones in a SELECT statement improves performance as opposed to using SELECT * because the current list is smaller.

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  • Javascript === vs == : Does it matter which "equal" operator I use?

    - by bcasp
    I'm using JSLint to go through some horrific JavaScript at work and it's returning a huge number of suggestions to replace == with === when doing things like comparing 'idSele_UNVEHtype.value.length == 0' inside of an if statement. I'm basically wondering if there is a performance benefit to replacing == with ===. Any performance improvement would probably be welcomed as there are hundreds (if not thousands) of these comparison operators being used throughout the file. I tried searching for relevant information to this question, but trying to search for something like '=== vs ==' doesn't seem to work so well with search engines...

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  • What is the best way to partition large tables in SQL Server?

    - by RyanFetz
    In a recent project the "lead" developer designed a database schema where "larger" tables would be split across two seperate databases with a view on the main database which unioned the two seperate database-tables together. The main database is what the application was driven off of so these tables looked and felt like ordinary tables (except some quirkly things around updating). This seemed like a HUGE performance problem. We do see problems with performance around these tables but nothing to make him change his mind about his design. Just wondering what is the best way to do this, or if it is even worth doing?

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  • USB device Set Attribute in C#

    - by p19lord
    I have this bit of code: DriveInfo[] myDrives = DriveInfo.GetDrives(); foreach (DriveInfo myDrive in myDrives) { if (myDrive.DriveType == DriveType.Removable) { string path = Convert.ToString(myDrive.RootDirectory); DirectoryInfo mydir = new DirectoryInfo(path); String[] dirs = new string[] {Convert.ToString(mydir.GetDirectories())}; String[] files = new string[] {Convert.ToString(mydir.GetFiles())}; foreach (var file in files) { File.SetAttributes(file, ~FileAttributes.Hidden); File.SetAttributes(file, ~FileAttributes.ReadOnly); } foreach (var dir in dirs) { File.SetAttributes(dir, ~FileAttributes.Hidden); File.SetAttributes(dir, ~FileAttributes.ReadOnly); } } } I have a problem. It is trying the code for Floppy Disk drive first which and because no Floppy disk in it, it threw the error The device is not ready. How can I prevent that?

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  • Any reason NOT to slap the 'synchronized' keyword everywhere?

    - by unknown
    In my java project, almost every non-static method I've written is synchronized. I've decided to fix up some code today, by removing most of the synchronized keywords. Right there I created several threading issues that took quite a while to fix, with no increase in performance. In the end I reverted everything. I don't see anyone else writing code with "synchronized" everywhere. So is there any reason I shouldn't have "synchronized" everywhere? What if I don't care too much about performance (ie. the method isn't called more than once every few seconds)?

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  • SqlCE Flush Interval - Will the default setting lead to corruption?

    - by NormD
    SqlCE has a parameter set on the Connect String called Flush Interval. It is defined as: The interval time (in seconds) before all committed transactions are flushed to disk. If not specified, the default value is 10. I thought that a committed transaction, by definition, is a transaction that has been flushed to disk, specifically the database file. If a transaction is only stored in RAM then cannot the transaction be easily lost? I thought that transactions were first written to a log file and then applied to the database file itself, so perhaps this parameter could mean the time to wait until the transaction log is applied to the database file? I would have thought that this parameter should be 0.

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  • Enable Php Fastcgi and Get 500 Internal Server Error (Lighttpd)

    - by skycrew
    anyone can help me? I just got this problem today. Before this my site running smooth with Fastcgi enable but now its show 500 internal server error with below logs. I need to disable php fastcgi in LxAdmin so that my visitor can access my site but when I disable php fastgi, my web performance is very slow with high load to server. I also include the performance screenshot. What should I do? This are the error log I got: 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 24055 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 21622 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 3342 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3207) child exited, pid: 3342 status: 0 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 836 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 836 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 22325 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 852 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 24032 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 20402 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 3336 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:52: (mod_fastcgi.c.3207) child exited, pid: 3336 status: 0 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 855 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:52: (mod_cgi.c.1231) cgi died ? 2010-06-16 21:59:53: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:53: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:53: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:53: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:53: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:53: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:53: (mod_fastcgi.c.1731) connect failed: Connection refused on unix:/var/tmp/lighttpd/php.socket.lyrics-hub.com.3333-1 2010-06-16 21:59:53: (mod_fastcgi.c.2885) backend died; we'll disable it for 5 seconds and send the request to another backend instead: reconnects: 0 load: 1 2010-06-16 21:59:56: (server.c.1470) server stopped by UID = 0 PID = 24439 2010-06-16 22:00:23: (log.c.75) server started Performance Graph as below:- http://img404.imageshack.us/img404/3498/memorylxadmin.jpg

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  • Enable Php Fastcgi and Get 500 Internal Server Error (Lighttpd)

    - by skycrew
    Hello everyone, anyone can help me? I just got this problem today. Before this my site running smooth with Fastcgi enable but now its show 500 internal server error with below logs. I need to disable php fastcgi in LxAdmin so that my visitor can access my site but when I disable php fastgi, my web performance is very slow with high load to server. I also include the performance screenshot. What should I do? This are the error log I got: 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 24055 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 21622 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 3342 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3207) child exited, pid: 3342 status: 0 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 836 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 836 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 22325 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24447 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 852 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-1 for /index.php , closing connection 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 24032 2010-06-16 21:59:52: (mod_cgi.c.584) cgi died, pid: 20402 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 3336 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:52: (mod_fastcgi.c.3207) child exited, pid: 3336 status: 0 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 855 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:52: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:52: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:52: (mod_cgi.c.1231) cgi died ? 2010-06-16 21:59:53: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:53: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:53: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:53: (mod_fastcgi.c.3254) response not received, request sent: 878 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:53: (mod_fastcgi.c.2462) unexpected end-of-file (perhaps the fastcgi process died): pid: 24448 socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 2010-06-16 21:59:53: (mod_fastcgi.c.3254) response not received, request sent: 860 on socket: unix:/var/tmp/lighttpd/php.socket.lyrics.skycrewz.net.3333-0 for /index.php , closing connection 2010-06-16 21:59:53: (mod_fastcgi.c.1731) connect failed: Connection refused on unix:/var/tmp/lighttpd/php.socket.lyrics-hub.com.3333-1 2010-06-16 21:59:53: (mod_fastcgi.c.2885) backend died; we'll disable it for 5 seconds and send the request to another backend instead: reconnects: 0 load: 1 2010-06-16 21:59:56: (server.c.1470) server stopped by UID = 0 PID = 24439 2010-06-16 22:00:23: (log.c.75) server started Performance Graph as below:- http://img404.imageshack.us/img404/3498/memorylxadmin.jpg

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  • Windows 7 .NET 3.5.1 - 2.0 Slightly Corrupted, How to Repair?

    - by Quinxy von Besiex
    My Windows 7 included .NET installation (3.5 to 2.0) appears very slightly and particularly corrupted and I am trying to fix it without reinstalling Windows or trying to revert to backups. Everything was working and then my hard drive started corrupting a few files and checkdisk found bad clusters so I imaged the drive to a new one. As soon as I booted on the new drive everything worked except programs which call the System.Net.NetworkInformation methods within .NET 3.5 to 2.0 (like Ping() and IsNetworkAvailable()), which immediately crash the app in which the calls are (those calls in .NET 4.0 works fine). Those methods are found inside System.dll, and I assume call native methods which I believe are inside winnsi.dll or iphlpapi.dll or something else (I've not found this yet); I assume it calls native methods because the exception which causes the crash is Fatal Execution Engine Error which people mention is usually related to calling native methods and marshaling data between them. A huge clue about the culprit is likely found in the fact that when I launch the exact same crashing application through a code profiler (which executes the exe and captures stats on which methods took the longest) the app works fine, no crash at all! How could running it within the profiler work and running it outside not work? That seems the key to the mystery. I've used procmon to catch all the registry, filesystem, and network events from the crashing execution and the profiler-run successful execution and compared the two outputs but didn't learn much (I see the moment at which the non-profiled app crashes, but up until then they behave the same, loaded the same modules, ). The only big difference seems to be that at the moment before the app crash the profiler-executed code creates 4-6 new threads and the directly executed code only creates 1-2. I have diffed the files/directories which seemed most relevant (the .NET stuff under Windows and Program Files) pre- and post- disk trouble and seen no changes where I didn't expect any (no obvious file corruption). I have diffed the software and system registry hives pre- and post- disk trouble and seen no changes which seemed relevant. I have created a new user account and cleaned up any environment variables in case environment was related. No change. I did "sfc /scannow" and it found no integrity problems. I tried "ngen update" to regenerate pre-compiled code in case I missed something that might be damaged and nothing changed. I assume I need to repair my .NET installation but because Windows 7 included .NET 3.5 - 2.0 you can't just re-run a .NET installer to redo it. I do not have access to the Windows disks to try to re-install Windows over itself (the computer has a recovery partition but it is unusable); also the drive uses a whole-disk encryption solution and re-installing would be difficult. I absolutely do not want to start from scratch here and install a fresh Windows, reinstall dozens of software packages, try and remember dozens of development-related customizations/etc. Given all that... does anyone have any helpful advice? I need .NET 3.5 - 2.0 working as I am a developer and need to build and test against it. Thanks! Quinxy

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  • KVM guest io is much slower than host io: is that normal?

    - by Evolver
    I have a Qemu-KVM host system setup on CentOS 6.3. Four 1TB SATA HDDs working in Software RAID10. Guest CentOS 6.3 is installed on separate LVM. People say that they see guest performance almost equal to host performance, but I don't see that. My i/o tests are showing 30-70% slower performance on guest than on host system. I tried to change scheduler (set elevator=deadline on host and elevator=noop on guest), set blkio.weight to 1000 in cgroup, change io to virtio... But none of these changes gave me any significant results. This is a guest .xml config part: <disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/dev/vgkvmnode/lv2'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </disk> There are my tests: Host system: iozone test # iozone -a -i0 -i1 -i2 -s8G -r64k random random KB reclen write rewrite read reread read write 8388608 64 189930 197436 266786 267254 28644 66642 dd read test: one process and then four simultaneous processes # dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct 1073741824 bytes (1.1 GB) copied, 4.23044 s, 254 MB/s # dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=1024 & dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=2048 & dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=3072 & dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=4096 1073741824 bytes (1.1 GB) copied, 14.4528 s, 74.3 MB/s 1073741824 bytes (1.1 GB) copied, 14.562 s, 73.7 MB/s 1073741824 bytes (1.1 GB) copied, 14.6341 s, 73.4 MB/s 1073741824 bytes (1.1 GB) copied, 14.7006 s, 73.0 MB/s dd write test: one process and then four simultaneous processes # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 6.2039 s, 173 MB/s # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test2 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test3 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test4 bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 32.7173 s, 32.8 MB/s 1073741824 bytes (1.1 GB) copied, 32.8868 s, 32.6 MB/s 1073741824 bytes (1.1 GB) copied, 32.9097 s, 32.6 MB/s 1073741824 bytes (1.1 GB) copied, 32.9688 s, 32.6 MB/s Guest system: iozone test # iozone -a -i0 -i1 -i2 -s512M -r64k random random KB reclen write rewrite read reread read write 524288 64 93374 154596 141193 149865 21394 46264 dd read test: one process and then four simultaneous processes # dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=1024 1073741824 bytes (1.1 GB) copied, 5.04356 s, 213 MB/s # dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=1024 & dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=2048 & dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=3072 & dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=4096 1073741824 bytes (1.1 GB) copied, 24.7348 s, 43.4 MB/s 1073741824 bytes (1.1 GB) copied, 24.7378 s, 43.4 MB/s 1073741824 bytes (1.1 GB) copied, 24.7408 s, 43.4 MB/s 1073741824 bytes (1.1 GB) copied, 24.744 s, 43.4 MB/s dd write test: one process and then four simultaneous processes # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 10.415 s, 103 MB/s # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test2 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test3 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test4 bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 49.8874 s, 21.5 MB/s 1073741824 bytes (1.1 GB) copied, 49.8608 s, 21.5 MB/s 1073741824 bytes (1.1 GB) copied, 49.8693 s, 21.5 MB/s 1073741824 bytes (1.1 GB) copied, 49.9427 s, 21.5 MB/s I wonder is that normal situation or did I missed something?

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  • Where's the Swap File/Partition?

    - by chrisbunney
    I'm investigating the virtual memory configuration of a Debian based Amazon EC2 instance, and as my background isn't in system admin, I'm slightly confused by what I'm seeing. We're using MongoDB, and the monitoring server we have indicates that the Mongo process is using about 20GB of swap space, however I can't figure out where this is located on the server. As far as I can tell from using the various suggested methods from Google, there is either a much smaller amount, or none at all. top indicates that there is 1.8GB of swap memory: top - 15:35:21 up 6 days, 3:23, 1 user, load average: 1.60, 1.43, 1.37 Tasks: 47 total, 2 running, 45 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 1.3%sy, 0.0%ni, 14.7%id, 83.8%wa, 0.0%hi, 0.0%si, 0.1%st Mem: 3928924k total, 2855572k used, 1073352k free, 640564k buffers Swap: 0k total, 0k used, 0k free, 1887788k cached swapon -s doesn't seem to think there's any swap space: Filename Type Size Used Priority free -m doesn't think there's any swap either: total used free shared buffers cached Mem: 3836 3663 172 0 626 2701 -/+ buffers/cache: 336 3500 Swap: 0 0 0 And neither does vmstat: procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 3 0 66224 641372 2874744 0 0 21 5012 21 33 2 2 76 19 But cat /etc/fstab thinks there is a swap partition: /dev/xvda1 / ext3 defaults 1 1 /dev/xvda2 /mnt ext3 defaults 0 0 /dev/xvda3 swap swap defaults 0 0 none /proc proc defaults 0 0 none /sys sysfs defaults 0 0 However df -k gives no indication of the xvda3 partition: Filesystem 1K-blocks Used Available Use% Mounted on /dev/xvda1 16513960 15675324 0 100% / tmpfs 1964460 8 1964452 1% /lib/init/rw udev 1914148 28 1914120 1% /dev tmpfs 1964460 4 1964456 1% /dev/shm So I really don't know what to make of this, because I appear to have a process using about 10 times more virtual memory than what might be available, and I have no idea where this virtual memory is on the system. I'm probably misinterpreting the output of the tools, so I'd be grateful if someone would be able to set me straight: What have I got wrong, what's the right interpretation, and how do you reach that interpretation? EDIT0: We use 10gen's MMS for monitoring the database, the relevant section for memory from the last data point is: "mem": { "virtual": 20749, "bits": 64, "supported": true, "mappedWithJournal": 20376, "mapped": 10188, "resident": 1219 }, This JSON is specific to the database process (I believe) rather than the system as a whole. fdisk -l /dev/xvda outputs... nothing? I tried each of the 3 xvda entries in /etc/fstab as well: root@ip:~# fdisk -l /dev/xvda1 Disk /dev/xvda1: 34.4 GB, 34359738368 bytes 255 heads, 63 sectors/track, 4177 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/xvda1 doesn't contain a valid partition table root@ip:~# fdisk -l /dev/xvda2 root@ip:~# fdisk -l /dev/xvda3 root@ip:~# Edit1: Output of cat /proc/meminfo for the sake of completeness: MemTotal: 3928924 kB MemFree: 726600 kB Buffers: 648368 kB Cached: 2216556 kB SwapCached: 0 kB Active: 1945100 kB Inactive: 994016 kB Active(anon): 60476 kB Inactive(anon): 12952 kB Active(file): 1884624 kB Inactive(file): 981064 kB Unevictable: 0 kB Mlocked: 0 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 387180 kB Writeback: 0 kB AnonPages: 73380 kB Mapped: 1188260 kB Shmem: 48 kB Slab: 149768 kB SReclaimable: 146076 kB SUnreclaim: 3692 kB KernelStack: 1104 kB PageTables: 16096 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 1964460 kB Committed_AS: 305572 kB VmallocTotal: 34359738367 kB VmallocUsed: 16760 kB VmallocChunk: 34359721448 kB HardwareCorrupted: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 3932160 kB DirectMap2M: 0 kB

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  • ESXI guests not using available CPU resources

    - by Alan M
    I have a VMWare ESXI 5.0.0 (it's a bit old, I know) host with three guest VMs on it. For reasons unknown, the guests will not use much of the availble CPU resources. I have all three guests in a single pool, with the hosts all configured to use the same amount of resource shares, so they're basically 33% each. The three guests are basically identically configured as far as their VM resources go. So the problem is, even when the guests are performing what should be very 'busy' activitites, such as at bootup, the actual host CPU consumed is something tiny, like 33mhz, when seen via vSphere console's "Virtual Machines" tab when viewing properties for the pool. And of course, the performance of the guest VMs is terrible. The host has plenty of CPU to spare. I've tried tinkering with individual guest VM resource settings; cranking up the reservation, etc. No matter. The guests just refuse to make use of the abundant CPU available to them, and insist on using a sliver of the available resources. Any suggestions? Update after reading various comments below Per the suggestions below, I did remove the guests from the application pool; this didn't make any difference. I do understand that the guests are not going to consume resources they do not need. I have tried to do a remote perfmon on the guest which is experiencing long boot times, but I cannot connect to the guest remotely with perfmon (guest is w2k8r2 server). Host graphs for CPU, Mem, Disk are basically flatlining; very little demand. Same is true for the guest stats; while the guest itself seems to be crawling, the guest resource graphing shows very little activity across CPU, Mem, Disk. Host is a Dell PowerEdge 2900, has 2 physical CPU,20gb RAM. (it's a test/dev environment using surplus gear) Guest1 has: VM ver. 7, 2vCPU, 4gb RAM, 140gb storage which lives on a RAID-5 array on the host. Guest2 has: VM ver. 7, 2vCPU, 4gb RAM, 140gb storage which lives on a RAID-5 array on the host. Guest3 has: VM ver. 7, 1vCPU, 2gb RAM, 2tb storage which lives on a RAID-5 ISCSI NAS box Perhaps I am making a false assumption that if a guest has a demand for CPU (e.g. Windows Task Manager shows 100% CPU), the host would supply the guest with more CPU (mem, disk) on demand. Another Update After checking the stats, it would appear that the host is indeed not busy at all, neither is the guest. I believe I have a good idea on the issue, though; a messed-up VMWare Tools install. The guest has VMware Tools on it, but the host says it does not. VMWare Tools refuses to uninstall, refuses to be upgraded, refuses to be recognized. While I cannot say with authority, this would appear to be something worth investigation. I do not know the origin of the guest itself, nor the specifics on the original VMWare Tools install. Following various bits of googling, I did come up with a few suggestions that went nowhere. To that end, I was going to delete this question, but was prompted not to do so since so many folks answered. My suspicion right now is; the problem truly is the guest; the guest is not making a demand on the host, and as a natural result, the host is treating the guest accordingly. My Final Update I am 99% certain the guest VM had something fundamentally wrong with it re VMWare Tools. I created a clone of a different VM with a near-identical OS config, but a properly working install of VMWare tools. The guest runs just great, and takes up it's allotment of resources when it needs to; e.g. it eats up about 850mhz CPU during startup, then ticks down to idle once the guest OS is stable.

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  • Unmountable boot volume blue screen, what should I do?

    - by Josh
    I was trying to install an update from NVIDIA for my GTX 560, but while it was installing, my computer shut off. After a few minutes, I turned it back on. It got to the Windows boot screen and then had a blue screen error and if left on it would just keep doing that. A few details about my PC: I haven't added any new hardware or software, I'm running Windows XP Professional 32 bit and Windows XP Professional 64 bit on the same hard drive for about 2 years now. I have 2 other hard drives also, but I don't have one large enough to hold everything from my main hard drive, so formatting isn't an option. Now, as for what I've done so far: I've scanned the RAM with "memtest - 86 v3.4" and it said that it was good. I scanned the hard drive in question with chkdsk /r and it gets to 50% and tells me something along the lines of "the drive has one or more unrepairable problems". I also tried to use chkdsk on the drive I installed the new copy of Windows XP on and it got to 75% then jumped back down to 50% and stayed there (I had to reboot the pc). So, after that, I turned off auto reboot and got to read the blue screen error code and I looked it up only to find that nobody seems to have this problem, just problems close to it. The error code is 0x000000ed and I've seen a lot of these online but none that matched the detailed part of the code UNMOUNTABLE_BOOT_VOLUME 0x000000ed (0xfffffadf513c19a0, 0xffffffffc0000006, 0, 0) So, I have installed another copy of Windows XP Professional 32 bit on one of my other hard drives in hopes of accessing the data on the drive in question and when it booted it asked if I wanted chkdsk to scan the drive in question and this is what it found: file record segments 12740, 12741, 12742 and 12743 were reported unreadable. Then it says "recovering lost files" but it sits there for a few seconds and then just boots to Windows. I can't access the drive in question from Windows as far as I can tell, it just says "drive not accessible" and when I go to properties it says that the drive has 100% free space. So, after that failed I didn't give up, I looked for another way to access the drive in question. I used a Ubuntu bootable disk and was able to access the drive in question without any problems. However, I can't access the registry editor because it's a .exe file and that won't load from Ubuntu. I made a copy of the "Windows" folder and put it on one of my other drives and that's where I'm stuck at now. I'm sure my drive works fine, I know chkdsk can't fix the problem with it and I know what caused the problem in the first place for the most part, but I don't know what to do about it. I have a laptop that I can use to download and burn disks if needed and I also have the other copy of Windows XP Professional 32 bit that I can use that's installed on the computer in question (so I know it's not a hardware issue). I'm pretty sure it's a driver issue or the update was editing the registry when it shut off and left me when a broken registry. I've tried accessing C:\Windows\System32\CONFIG only to find that the Windows XP disk repair option can't even access the files on the drive in question. It seems I'll need to be able to do everything from Ubuntu unless there is something I haven't tried with the Windows XP disk. I didn't install the update on Windows XP 64 bit but yet it also has the same blue screen error (that's where the error code above came from but I haven't checked to see if they are the same). They both stopped working at the same time, so I assume it's one problem causing both to not work.

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  • Understanding NFS4 (Linux server)

    - by drumfire
    I've been a bit bothered by NFS4 on Linux. Some information 'out there' seems to conflict with other information, and other information appears hard to find. So here are a couple of things that caught my attention, hopefully someone out there can shed some light on this. This question focuses exclusively on NFS4 without Kerberos etc. 1. Exports There is ambiguous information in the exports manpage on the structure of /etc/exports. To quote from exports(5): Also, each line may have one or more specifications for default options after the path name, in the form of a dash ("-") followed by an option list. The option list is used for all subsequent exports on that line only. What does "subsequent exports on that line only" mean? 1.2 fsid=0 not required anymore? I was searching for fsid when I found a comment on the linux-nfs list stating fsid=0 is not required anymore. Now I'm just confused, do I need it with nfs4 or not?! 2. Non-exported directory still mountable Say I have the following tree: /exp /exp/users /exp/distr /exp/distr/archlinux /exp/distr/debian And I have the following entries in this fstab entry: /dev/disk/by-label/users /mnt/users ext4 defaults 0 0 /dev/disk/by-label/distr /mnt/distr ext4 defaults 0 0 /mnt/users /exp/users none bind 0 0 /mnt/distr /exp/distr none bind 0 0 And my exports is exactly this: /exp 192.168.1.0/24(fsid=0,rw,async,no_subtree_check,no_root_squash) /exp/distr 192.168.1.0/24(rw,async,no_subtree_check,no_root_squash) And exportfs -arv shows: exporting 192.168.1.0/24:/exp/distr exporting 192.168.1.0/24:/exp Then why am I able to do this and get no error on a client: mount -t nfs4 server:/exp/users /tmp/test Even though /exp/users is not exported? I didn't export this directory, and while I don't see the contents of /dev/disk/by-label/users unless I specify crossmnt, I am still able to write to the directory. Everything I write to there goes to the underlying directory of /exp/users which can be seen when I umount /exp/users; ls /exp/users.. 3. The odd case of showmount -d server As stated by rpc.mountd(8), this command should display directories that are either currently mounted by clients, or stale entries in /var/lib/nfs/rmtab, as can be read: The rpc.mountd daemon registers every successful MNT request by adding an entry to the /var/lib/nfs/rmtab file. When receivng a UMNT request from an NFS client, rpc.mountd simply removes the matching entry from /var/lib/nfs/rmtab, as long as the access control list for that export allows that sender to access the export. (...) Note, however, that there is little to guarantee that the contents of /var/lib/nfs/rmtab are accurate. A client may continue accessing an export even after invoking UMNT. If the client reboots without sending a UMNT request, stale entries remain for that client in /var/lib/nfs/rmtab. After reading this I surely wonder: Isn't it terribly insecure to just expose this type of client information; Aren't unaware server admins bound to have an rmtab with a lot of stale clients; Is this the reason that clients that mount nfs4 directories with mount -v get to see output like "nothing was mounted" even though something was mounted? I have a lot of other questions regarding nfs4, but I'll keep it at this for the moment.. :)

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  • Nagios notifications definitions

    - by Colin
    I am trying to monitor a web server in such a way that I want to search for a particular string on a page via http. The command is defined in command.cfg as follows # 'check_http-mysite command definition' define command { command_name check_http-mysite command_line /usr/lib/nagios/plugins/check_http -H mysite.example.com -s "Some text" } # 'notify-host-by-sms' command definition define command { command_name notify-host-by-sms command_line /usr/bin/send_sms $CONTACTPAGER$ "Nagios - $NOTIFICATIONTYPE$ :Host$HOSTALIAS$ is $HOSTSTATE$ ($OUTPUT$)" } # 'notify-service-by-sms' command definition define command { command_name notify-service-by-sms command_line /usr/bin/send_sms $CONTACTPAGER$ "Nagios - $NOTIFICATIONTYPE$: $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ ($OUTPUT$)" } Now if nagios doesn't find "Some text" on the home page mysite.example.com, nagios should notify a contact via sms through the Clickatell http API which I have a script for that that I have tested and found that it works fine. Whenever I change the command definition to search for a string which is not on the page, and restart nagios, I can see on the web interface that the string was not found. What I don't understand is why isn't the notification sent though I have defined the host, hostgroup, contact, contactgroup and service and so forth. What I'm I missing, these are my definitions, In my web access through the cgi I can see that I have notifications have been defined and enabled though I don't get both email and sms notifications during hard status changes. host.cfg define host { use generic-host host_name HAL alias IBM-1 address xxx.xxx.xxx.xxx check_command check_http-mysite } *hostgroups_nagios2.cfg* # my website define hostgroup{ hostgroup_name my-servers alias All My Servers members HAL } *contacts_nagios2.cfg* define contact { contact_name colin alias Colin Y service_notification_period 24x7 host_notification_period 24x7 service_notification_options w,u,c,r,f,s host_notification_options d,u,r,f,s service_notification_commands notify-service-by-email,notify-service-by-sms host_notification_commands notify-host-by-email,notify-host-by-sms email [email protected] pager +254xxxxxxxxx } define contactgroup{ contactgroup_name site_admin alias Site Administrator members colin } *services_nagios2.cfg* # check for particular string in page via http define service { hostgroup_name my-servers service_description STRING CHECK check_command check_http-mysite use generic-service notification_interval 0 ; set > 0 if you want to be renotified contacts colin contact_groups site_admin } Could someone please tell me where I'm going wrong. Here are the generic-host and generic-service definitions *generic-service_nagios2.cfg* # generic service template definition define service{ name generic-service ; The 'name' of this service template active_checks_enabled 1 ; Active service checks are enabled passive_checks_enabled 1 ; Passive service checks are enabled/accepted parallelize_check 1 ; Active service checks should be parallelized (disabling this can lead to major performance problems) obsess_over_service 1 ; We should obsess over this service (if necessary) check_freshness 0 ; Default is to NOT check service 'freshness' notifications_enabled 1 ; Service notifications are enabled event_handler_enabled 1 ; Service event handler is enabled flap_detection_enabled 1 ; Flap detection is enabled failure_prediction_enabled 1 ; Failure prediction is enabled process_perf_data 1 ; Process performance data retain_status_information 1 ; Retain status information across program restarts retain_nonstatus_information 1 ; Retain non-status information across program restarts notification_interval 0 ; Only send notifications on status change by default. is_volatile 0 check_period 24x7 normal_check_interval 5 retry_check_interval 1 max_check_attempts 4 notification_period 24x7 notification_options w,u,c,r contact_groups site_admin register 0 ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL SERVICE, JUST A TEMPLATE! } *generic-host_nagios2.cfg* define host{ name generic-host ; The name of this host template notifications_enabled 1 ; Host notifications are enabled event_handler_enabled 1 ; Host event handler is enabled flap_detection_enabled 1 ; Flap detection is enabled failure_prediction_enabled 1 ; Failure prediction is enabled process_perf_data 1 ; Process performance data retain_status_information 1 ; Retain status information across program restarts retain_nonstatus_information 1 ; Retain non-status information across program restarts max_check_attempts 10 notification_interval 0 notification_period 24x7 notification_options d,u,r contact_groups site_admin register 1 ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE! }

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  • Windows 7: How to place SuperFetch cache on an SSD?

    - by Ian Boyd
    I'm thinking of adding a solid state drive (SSD) to my existing Windows 7 installation. I know I can (and should) move my paging file to the SSD: Should the pagefile be placed on SSDs? Yes. Most pagefile operations are small random reads or larger sequential writes, both of which are types of operations that SSDs handle well. In looking at telemetry data from thousands of traces and focusing on pagefile reads and writes, we find that Pagefile.sys reads outnumber pagefile.sys writes by about 40 to 1, Pagefile.sys read sizes are typically quite small, with 67% less than or equal to 4 KB, and 88% less than 16 KB. Pagefile.sys writes are relatively large, with 62% greater than or equal to 128 KB and 45% being exactly 1 MB in size. In fact, given typical pagefile reference patterns and the favorable performance characteristics SSDs have on those patterns, there are few files better than the pagefile to place on an SSD. What I don't know is if I even can put a SuperFetch cache (i.e. ReadyBoost cache) on the solid state drive. I want to get the benefit of Windows being able to cache gigabytes of frequently accessed data on a relativly small (e.g. 30GB) solid state drive. This is exactly what SuperFetch+ReadyBoost (or SuperFetch+ReadyDrive) was designed for. Will Windows offer (or let) me place a ReadyBoost cache on a solid state flash drive connected via SATA? A problem with the ReadyBoost cache over the ReadyDrive cache is that the ReadyBoost cache does not survive between reboots. The cache is encrypted with a per-session key, making its existing contents unusable during boot and SuperFetch pre-fetching during login. Update One I know that Windows Vista limited you to only one ReadyBoost.sfcache file (I do not know if Windows 7 removed that limitation): Q: Can use use multiple devices for EMDs? A: Nope. We've limited Vista to one ReadyBoost per machine Q: Why just one device? A: Time and quality. Since this is the first revision of the feature, we decided to focus on making the single device exceptional, without the difficulties of managing multiple caches. We like the idea, though, and it's under consideration for future versions. I also know that the 4GB limit on the cache file was a limitation of the FAT filesystem used on most USB sticks - an SSD drive would be formatted with NTFS: Q: What's the largest amount of flash that I can use for ReadyBoost? A: You can use up to 4GB of flash for ReadyBoost (which turns out to be 8GB of cache w/ the compression) Q: Why can't I use more than 4GB of flash? A: The FAT32 filesystem limits our ReadyBoost.sfcache file to 4GB Can a ReadyBoost cache on an NTFS volume be larger than 4GB? Update Two The ReadyBoost cache is encrypted with a per-boot session key. This means that the cache has to be re-built after each boot, and cannot be used to help speed boot times, or latency from login to usable. Windows ReadyDrive technology takes advantage of non-volatile (NV) memory (i.e. flash) that is incorporated with some hybrid hard drives. This flash cache can be used to help Windows boot, or resume from hibernate faster. Will Windows 7 use an internal SSD drive as a ReadyBoost/*ReadyDrive*/SuperFetch cache? Is it possible to make Windows store a SuperFetch cache (i.e. ReadyBoost) on a non-removable SSD? Is it possible to not encrypt the ReadyBoost cache, and if so will Windows 7 use the cache at boot time? See also SuperUser.com: ReadyBoost + SSD = ? Windows 7 - ReadyBoost & SSD drives? Support and Q&A for Solid-State Drives Using SDD as a cache for HDD, is there a solution? Performance increase using SSD for paging/fetch/cache or ReadyBoost? (Win7) Windows 7 To Boost SSD Performance How to Disable Nonvolatile Caching

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  • IBM Server Config questions

    - by Joel Coel
    I have a few questions on a potential server setup. First, the situation: Last year we bought an IBM x3500 server with 2 Xeon E5410's, 9GB RAM, 6 HDDs. The original intent for this server was to replace the old exchange e-mail server. It was brought in, set up, and then shortly after we switched to gmail. Shortly after that my predecessor left for greener pastures, and finally I was hired. So this nice server is now sitting (mostly) idle. This year I have budget again for one server, and of course I want to put this other server to work. I'm thinking about the best use for the two server, and I think I finally have a plan for what I want to do with them. The idea is to use the two newer servers as a pair of VM hosts. I will set up each server with the same 8 VMs, but divide up the load so that only 4 are active per physical host. That means I've normally got 2GB RAM + 2 cores per host. I've done some load testing to pick out what servers to convert to virtual, and chose them so that each host will be capable of handling the entire set of 8 by itself in a pinch with 1 core and 1GB RAM, but would be very taxed to do so. This should take our data center from 13 total servers down to 7. The "servers" I'm replacing are mostly re-purposed desktops, so I'm more than happy to be able to do this. Now it's time to go shopping for the new server. I'd like my two hosts to match as closely as possible, and so I'm looking at IBM again. It also helps that we have some educational matching grant money from IBM that I need to use to help pay for this system (we're a small private college). So finally, (if you're not bored already), we come to my questions: Am I missing anything big or obvious in this plan? I'm a little worried about network performance since the VM hosts will only have 4 nics total where 8 used to be, but I don't think it will be a problem. Is there anything else like this I might be overlooking? Am I making it even too complicated? IBM no longer has a good analog to last year's server. If I want to match the performance (8 cores, 9GB RAM, 1333mhz front side bus, 6 spindles), I have to spend quite a bit more than we paid last year: $2K+, or nearly a 33% cost increase. This only brings a marginal increase in performance. The alternative to stay in budget is to take a hit on the fsb down to 800mhz or cut the number of cores in half, neither of which is attractive. The main cost culprit is the processor. IBM no longer offers the E5410. It's listed as a part, but not available in any of the server configs I've looked at. I'm considering getting the cheapest 800mhz fsb dual core xeon I can configure and then buying the E5410's separately. That's still an extra $350 I wasn't counting on, but that's better than $2K. I want to know what others think of this - will it work or will I end up with the wrong motherboard or some other issue? Am I missing a simple way to configure the server I really want? I don't really intend to do this, but one option to save some money back is to omit the redundant power supply. Since my redundancy plan for these system is to switch over to a completely different host, the extra power isn't fully necessary. That said, it's still very helpful to avoid even short downtimes while I switch over VMs. Has anyone done this?

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  • How to place SuperFetch cache on an SSD?

    - by Ian Boyd
    I'm thinking of adding a solid state drive (SSD) to my existing Windows 7 installation. I know I can (and should) move my paging file to the SSD: Should the pagefile be placed on SSDs? Yes. Most pagefile operations are small random reads or larger sequential writes, both of which are types of operations that SSDs handle well. In looking at telemetry data from thousands of traces and focusing on pagefile reads and writes, we find that Pagefile.sys reads outnumber pagefile.sys writes by about 40 to 1, Pagefile.sys read sizes are typically quite small, with 67% less than or equal to 4 KB, and 88% less than 16 KB. Pagefile.sys writes are relatively large, with 62% greater than or equal to 128 KB and 45% being exactly 1 MB in size. In fact, given typical pagefile reference patterns and the favorable performance characteristics SSDs have on those patterns, there are few files better than the pagefile to place on an SSD. What I don't know is if I even can put a SuperFetch cache (i.e. ReadyBoost cache) on the solid state drive. I want to get the benefit of Windows being able to cache gigabytes of frequently accessed data on a relativly small (e.g. 30GB) solid state drive. This is exactly what SuperFetch+ReadyBoost (or SuperFetch+ReadyDrive) was designed for. Will Windows offer (or let) me place a ReadyBoost cache on a solid state flash drive connected via SATA? A problem with the ReadyBoost cache over the ReadyDrive cache is that the ReadyBoost cache does not survive between reboots. The cache is encrypted with a per-session key, making its existing contents unusable during boot and SuperFetch pre-fetching during login. Update One I know that Windows Vista limited you to only one ReadyBoost.sfcache file (I do not know if Windows 7 removed that limitation): Q: Can use use multiple devices for EMDs? A: Nope. We've limited Vista to one ReadyBoost per machine Q: Why just one device? A: Time and quality. Since this is the first revision of the feature, we decided to focus on making the single device exceptional, without the difficulties of managing multiple caches. We like the idea, though, and it's under consideration for future versions. I also know that the 4GB limit on the cache file was a limitation of the FAT filesystem used on most USB sticks - an SSD drive would be formatted with NTFS: Q: What's the largest amount of flash that I can use for ReadyBoost? A: You can use up to 4GB of flash for ReadyBoost (which turns out to be 8GB of cache w/ the compression) Q: Why can't I use more than 4GB of flash? A: The FAT32 filesystem limits our ReadyBoost.sfcache file to 4GB Can a ReadyBoost cache on an NTFS volume be larger than 4GB? Update Two The ReadyBoost cache is encrypted with a per-boot session key. This means that the cache has to be re-built after each boot, and cannot be used to help speed boot times, or latency from login to usable. Windows ReadyDrive technology takes advantage of non-volatile (NV) memory (i.e. flash) that is incorporated with some hybrid hard drives. This flash cache can be used to help Windows boot, or resume from hibernate faster. Will Windows 7 use an internal SSD drive as a ReadyBoost/*ReadyDrive*/SuperFetch cache? Is it possible to make Windows store a SuperFetch cache (i.e. ReadyBoost) on a non-removable SSD? Is it possible to not encrypt the ReadyBoost cache, and if so will Windows 7 use the cache at boot time? See also SuperUser.com: ReadyBoost + SSD = ? Windows 7 - ReadyBoost & SSD drives? Support and Q&A for Solid-State Drives Using SDD as a cache for HDD, is there a solution? Performance increase using SSD for paging/fetch/cache or ReadyBoost? (Win7) Windows 7 To Boost SSD Performance How to Disable Nonvolatile Caching

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  • Centos 7. Freeradius fails to start on boot

    - by Alex
    I was messing around with FreeRADIUS and MySQL (MariaDB) and it seems FreeRADIUS service can't start properly on startup. But it starts fine using root user or in debug mode (radiusd -X) and works just fine! Debug mode shows no errors. systemctl command shows that radiusd.service has failed to start. /var/log/messages output: Aug 21 15:52:29 nexus-test systemd: Starting The Apache HTTP Server... Aug 21 15:52:29 nexus-test systemd: Starting MariaDB database server... Aug 21 15:52:29 nexus-test systemd: Starting FreeRADIUS high performance RADIUS server.... Aug 21 15:52:29 nexus-test systemd: Started OpenSSH server daemon. Aug 21 15:52:29 nexus-test mysqld_safe: 140821 15:52:29 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'. Aug 21 15:52:29 nexus-test mysqld_safe: 140821 15:52:29 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql Aug 21 15:52:30 nexus-test systemd: Started Postfix Mail Transport Agent. Aug 21 15:52:30 nexus-test avahi-daemon[604]: Registering new address record for fe80::250:56ff:fe85:e4af on eth0.*. Aug 21 15:52:30 nexus-test systemd: radiusd.service: control process exited, code=exited status=1 Aug 21 15:52:30 nexus-test systemd: Failed to start FreeRADIUS high performance RADIUS server.. Aug 21 15:52:30 nexus-test systemd: Unit radiusd.service entered failed state. Aug 21 15:52:31 nexus-test kdumpctl: kexec: loaded kdump kernel Aug 21 15:52:31 nexus-test kdumpctl: Starting kdump: [OK] Aug 21 15:52:31 nexus-test systemd: Started Crash recovery kernel arming. Aug 21 15:52:31 nexus-test systemd: Started The Apache HTTP Server. Aug 21 15:52:31 nexus-test systemd: Started MariaDB database server. /var/log/radius/radius.log output: Thu Aug 21 15:24:16 2014 : Info: rlm_sql (sql): Driver rlm_sql_mysql (module rlm_sql_mysql) loaded and linked Thu Aug 21 15:24:16 2014 : Info: rlm_sql (sql): Attempting to connect to database "radius" Thu Aug 21 15:24:16 2014 : Info: rlm_sql (sql): Opening additional connection (0) Thu Aug 21 15:24:16 2014 : Error: rlm_sql_mysql: Couldn't connect socket to MySQL server radius@localhost:radius Thu Aug 21 15:24:16 2014 : Error: rlm_sql_mysql: Mysql error 'Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)' Thu Aug 21 15:24:16 2014 : Error: rlm_sql (sql): Opening connection failed (0) Thu Aug 21 15:24:16 2014 : Error: /etc/raddb/mods-enabled/sql[47]: Instantiation failed for module "sql" After seeing this I tried to replicate the problem, killed mariadb.service and started to run debug mode again. And it spits out the same problem as in the radius.log. I tried disabling iptables and firewalld and rebooting, but no luck: systemctl disable iptables systemctl disable firewalld So maybe the problem is in the process startup order or delay of some kind. Maybe FreeRADIUS's SQL module can't connect to not yet started MariaDB? If it, how can I fix this? In earlier versions of RHEL/CENTOS I know you easily see service start order in like rc.d or stuff, now IDK. I am new to this fancy "systemd", "systemctl", "firewalld" stuff Centos 7 introduced so sorry I'm a little bit confused. Also this new FreeRADIUS 3 structure... PS. MariaDB is enabled on startup, credentials in FR DB configuration are correct A little update: cat /etc/systemd/system/multi-user.target.wants/radiusd.service output: [Unit] Description=FreeRADIUS high performance RADIUS server. After=syslog.target network.target [Service] Type=forking PIDFile=/var/run/radiusd/radiusd.pid ExecStartPre=-/bin/chown -R radiusd.radiusd /var/run/radiusd ExecStartPre=/usr/sbin/radiusd -C ExecStart=/usr/sbin/radiusd -d /etc/raddb ExecReload=/usr/sbin/radiusd -C ExecReload=/bin/kill -HUP $MAINPID [Install] WantedBy=multi-user.target

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