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• JFFS2 poor mount performance

  - by Marcin Polkowski

  I run multiple ARM boards with Debian Linux installed. Board is equipped with 512 MB of NAND memory. I've observed that after ~3 months of continuous run booting time increased significantly - it takes over 3 minutes to mount filesystem (JFFS2). System was using about 35% of available storage so I’ve removed unnecessary files (got to ~18%) but this didn't change anything. Then I realized that my software produces directories that are left empty so I’ve removed ~500 empty and unnecessary dirs. This didn’t help either. After system is started I see JFFS2 garbage collector (jffs2_gcd_mtd4) running and occupying over 90% of CPU. Now my question: is there a way to „optimize” JFFS2 filesystem for better performance - faster booting (my system have limited timid to boot up)? It would be great if this optimization could be done remotely - I have no physical access to boards.

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• server performance metrics report and practicality

  - by Anjesh

  I have a need of preparing web server (apache-php) performance report containing important metrics like CPU usage, disk io, memory usage on user basis. Couple of domains are hosted in the same server and they run from separate users using fcgi. The reason being sometimes some hosted applications take lots of cpu usage, making the server slow for other applications (running as separate users). i am planning to develop scripts for this, as i can't seem to find any simple utilities for this purpose. This script will take snapshots of the user wise metrics at defined periods say 15 minutes and record it. Any abnormalities will be reported via emails. How practical is that? also would be interesting to know what else need to be recorded.

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• How do you demonstrate performance in paired-programming environments?

  - by NT3RP

  Performance reviews have come up recently at my work, and I was put in an interesting position. Our team does a lot of pair programming, which has a tendency of averaging out the skill differences between team members (especially considering we rotate pairs). Generally, when doing performance reviews, you look back at the work you've done, and demonstrate what you've accomplished, and how you've exceeded expectations to try to negotiate a raise or other benefits. How do you demonstrate (or even measure) individual performance in an environment like this?

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• procedure that swaps the bytes (low/high) of a Word variable

  - by Altar

  Hi. I have this procedure that swaps the bytes (low/high) of a Word variable (It does the same stuff as System.Swap function). The procedure works when the compiler optimization is OFF but not when it is ON. Can anybody help me with this? { UNSAFE! IT IS NOW WORKING WHEN COMPILER OPTIMIZATION IS ON ! } procedure SwapWord_NotWorking(VAR TwoBytes: word); asm Mov EBX, TwoBytes Mov AX, [EBX] XCHG AL,AH Mov [EBX], AX end;

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• Wireless performance on Ubuntu 9.10

  - by Brian

  Is there something I should do to my networking configuration in Ubuntu to better the performance of my wireless connection? I'm on a netbook dual-booting Windows 7 and Ubuntu 9.10. I pick up much stronger wifi signal when in Windows than Ubuntu. As soon as I boot Ubuntu, it will connect to the network with a stronger signal, and then loses signal very quickly. After it dies, I can't reconnect. I've tested this on a couple of different networks with the same outcome.

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• Performance & Security Factors of Symbolic Links

  - by Stoosh

  I am thinking about rolling out a very stripped down version of release management for some PHP apps I have running. Essentially the plan is to store each release in /home/release/1.x etc (exported from a tag in SVN) and then do a symlink to /live_folder and change the document root in the apache config. I don't have a problem with setting all this up (I've actually got it working at the moment), however I'm a developer with just basic knowledge of the server admin side of things. Is there anything I need to be aware of from a security or performance perspective when using this method of release management? Thanks

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• SSIS Package performance during bulk insert

  - by vartika

  SSIS performance degrades when using bulk insert task in for each loop to upload multiple files into one target table. how to maintain SSIS performance

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• Best Embedded SQL DB for write performance?

  - by max.minimus

  Has anybody done any benchmarking/evaluation of the popular open-source embedded SQL DBs for performance, particularly write performance? I've some 1:1 comparisons for sqlite, Firebird Embedded, Derby and HSQLDB (others I am missing?) but no across the board comparisons... Also, I'd be interested in the overall developer experience for any of these (for a Java app).

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• how to fast compute distance between high dimension vectors

  - by chyojn

  assume there are three group of high dimension vectors: {a_1, a_2, ..., a_N}, {b_1, b_2, ... , b_N}, {c_1, c_2, ..., c_N}. each of my vector can be represented as: x = a_i + b_j + c_k, where 1 <=i, j, k <= N. then the vector is encoded as (i, j, k) wich is then can be decoded as x = a_i + b_j + c_k. my question is, if there are two vector: x = (i_1, j_1, k_1), y = (i_2, j_2, k_2), is there a method to compute the euclidian distance of these two vector without decode x and y.

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• Networking with extremely high latency.

  - by BCS

  Are there any protocols, systems, etc. experimental or otherwise designed for allowing normal (as normal as can be) network operations (E-mail, DNS, HTML, etc.) over very high latency links? I'm thinking of minutes to an hour, or maybe two. Think light speed lag at a solar system scale.

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• Windows web server and SQL Server on same dedicated server

  - by asinc

  I'm currently trying to decide on the best approach to handle hosting a few moderate traffic websites for production e-commerce and online applications. We'd like to move to a dedicated server and are looking at this as the most likely machine: Quad Core Intel Core2Quad Q9550 Processor, 2.83 Ghz X 4, 4 GB Kingston Ram This would run Windows Web Server 2008 R2 x64 and potentially also Sql Server Web 2008 and SmarterMail server. Given that we already pay for a high-end VPS for development, testing, shared version control we'd like to avoid going with two servers for production. We'd like to avoid using shared sql server hosting and have thought of using the development server as the database server as an option too - but potentially a security risk due to use for development by internal and contract users. The questions are: - Do you feel there would be performance degradation by running this on the same machine? - Are there significant issues to be concerned about if we do this? We understand that best practice would be to run separate db and app servers but the volume of traffic is currently not that high and adding another server just for database is currently too costly. - What are others doing out there? Alternatively, would you recommend instead going with two separate VPS servers with 2GB RAM each on Hyper-v which would be about the same cost as the single dedicated server above? Thanks!

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• In Windows 7, why can't I use perfmon against a remote server?

  - by SomeGuy

  I am on Windows 7 and trying to run perfmon against Windows 2003 and Windows 2008 servers. I am running into the same issue with all remote machines. When creating a data collector set, I specify a domain account that is in the administrators group on the remote machines (and "Performance Log Users" and "Performance Monitor Users" to be safe). On the "Available Counters" screen, When I type in a remote computer name, PerfMon locks up for a good 2-3 minutes before I can add any counters. I can then save the collector set. However, when I save it, the go/stop buttons are disabled if I click the set in the left panel, and missing if I click the Data collector set itself in the right panel. See the screens below. I can run data collector sets against my local machine with no problem. I am opening perfmon with my local account in both scenarios. I also have Remote Registry Service started on each remote machine. What is going on?

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• Send mail on event log error trigger safe check frequency

  - by Zeb Rawnsley

  I want to use powershell to alert me when an error occurs in the event viewer on my new Win2k12 Standard Server, I was thinking I could have the script execute every 10mins but don't want to put any strain on the server just for event log checking, here is the powershell script I want to use: $SystemErrors = Get-EventLog System | Where-Object { $_.EntryType -eq "Error" } If ($SystemErrors.Length -gt 0) { Send-MailMessage -To "[email protected]" -From $env:COMPUTERNAME + @company.co.nz" -Subject $env:COMPUTERNAME + " System Errors" -SmtpServer "smtp.company.co.nz" -Priority High } What is a safe frequency I can run this script at without hurting my server? Hardware: Intel Xeon E5410 @ 2.33GHz x2 32GB RAM 3x 7200RPM S-ATA 1TB (2x RAID1) Edit: With the help of Mathias R. Jessen's answer, I ended up attaching an event to the application & system log with the following script: Param( [string]$LogName ) $ComputerName = $env:COMPUTERNAME; $To = "[email protected]" $From = $ComputerName + "@company.co.nz"; $Subject = $ComputerName + " " + $LogName + " Error"; $SmtpServer = "smtp.company.co.nz"; $AppErrorEvent = Get-EventLog $LogName -Newest 1 | Where-Object { $_.EntryType -eq "Error" }; If ($AppErrorEvent.Length -eq 1) { $AppErrorEventString = $AppErrorEvent | Format-List | Out-String; Send-MailMessage -To $To -From $From -Subject $Subject -Body $AppErrorEventString -SmtpServer $SmtpServer -Priority High; };

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• Is basing storage requirements based on IOPS sufficient?

  - by Boden

  The current system in question is running SBS 2003, and is going to be migrated on new hardware to SBS 2008. Currently I'm seeing on average 200-300 disk transfers per second total across all the arrays in the system. The array seeing the bulk of activity is a 6 disk 7200RPM RAID 6 and it struggles to keep up during high traffic times (idle time often only 10-20%; response times peaking 20-50+ ms). Based on some rough calculations this makes sense (avg ~245 IOPS on this array at 70/30 read to write ratio). I'm considering using a much simpler disk configuration using a single RAID 10 array of 10K disks. Using the same parameters for my calculations above, I'm getting 583 average random IOPS / sec. Granted SBS 2008 is not the same beast as 2003, but I'd like to make the assumption that it'll be similar in terms of disk performance, if not better (Exchange 2007 is easier on the disk and there's no ISA server). Am I correct in believing that the proposed system will be sufficient in terms of performance, or am I missing something? I've read so much about recommended disk configurations for various products like Exchange, and they often mention things like dedicating spindles to logs, etc. I understand the reasoning behind this, but if I've got more than enough random I/O overhead, does it really matter? I've always at the very least had separate spindles for the OS, but I could really reduce cost and complexity if I just had a single, good performing array. So as not to make you guys do my job for me, the generic version of this question is: if I have a projected IOPS figure for a new system, is it sufficient to use this value alone to spec the storage, ignoring "best practice" configurations? (given similar technology, not going from DAS to SAN or anything)

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• Determining a realistic measure of requests per second for a web server

  - by Don

  I'm setting up a nginx stack and optimizing the configuration before going live. Running ab to stress test the machine, I was disappointed to see things topping out at 150 requests per second with a significant number of requests taking 1 second to return. Oddly, the machine itself wasn't even breathing hard. I finally thought to ping the box and saw ping times around 100-125 ms. (The machine, to my surprise, is across the country). So, it seems like network latency is dominating my testing. Running the same tests from a machine on the same network as the server (ping times < 1ms) and I see 5000 requests per second, which is more in-line with what I expected from the machine. But this got me thinking: How do I determine and report a "realistic" measure of requests per second for a web server? You always see claims about performance, but shouldn't network latency be taken into consideration? Sure I can serve 5000 request per second to a machine next to the server, but not to a machine across the country. If I have a lot of slow connections, they will eventually impact my server's performance, right? Or am I thinking about this all wrong? Forgive me if this is network engineering 101 stuff. I'm a developer by trade. Update: Edited for clarity.

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• Different network response for indentical co-located machines

  - by Santosh

  We have a situation as follows: We have a two different virtual machines (VMs) on some remote server farm. The machines are identical in terms of hardware/software(OS) configurations. We have a J2EE application running on JBoss on each of those two machines. These two applications are of different version sav V1 on VM1 and V2 on VM2. We observed some degraded response time for application V2 when accessed via public URL. When we accessed the application through a secured VPN, there is hardly any difference. The bandwidth test (upload/download speed, ping etc) shows that VM1 is responding better when accessed via secured VPN. We concluded that the application does not seem to have performance issue. Because, it that's the case the performance degradation should also be there when access via VPN. So we concluded its the network problem. But since those two identical VMs are on same network we are looking for the reasons for different responses. My question is, given the above situation, what could be reasons for such a behavior ?

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• Postfix spool on ext3 optimiziations in >=linux-2.6.34 days

  - by Luke404

  Given the very specific nature of the subject (we're not talking about mailboxes, just the spool; we're not talking about other filesystems, just ext3; and so on...) and the maturity of the softwares involved (linux kernel, ext3fs, postfix) I'd think there should be a more or less agreed on set of best practices to filesystem related tuning. I'm trying to get a roundup of them: data=journal became the default in recent kernels (somewhere around 2.6.30 IIRC) so we should be ok with that Wietse Venema says atime must be on, but Postfix documentation recommendsnoatime while talking about the Incoming Queue. Does that mean that postfix needs atime on just for some queue directories and will benefit from noatime on the others? can we use noatime if we just don't use ETRN? filesystem can be mounted nodev,noexec,nosuid - no* won't prevent you from setting attributes (postfix uses exec attr) they just won't have any effect (we don't run anything from the spool) the fsync() issue cited by Wietse and/or the chattr -S are probably linked to sync/async options of ext3fs but I do not understand them enough. Mouting the filesystem with async option is equivalent to chattr -R -S the whole fs? Seems like it will increase performance, but will that pose a risk of "loss of mail after a system crash" or is it really "safe on /var/spool/postfix" ? would you tune anything else on postfix-2.6.x to work better on ext3 or do you leave defaults everywhere? is there a "best" linux I/O scheduler for this kind of workload (namely CFQ or deadline?) or that's something that will vary too much based on hardware configuration? would you tune anything else in the filesystem or in the kernel? anything else? References: Postfix Performance here on SF Postfix documentation about the Incoming Queue Wietse Venema in Best file system on [email protected] here Postfix and ext3 on [email protected] here and there

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• Some free cloud solution to enhance your business

  - by Saif Bechan

  I am co-owner of a small internet business. I am in charge of IT, and I try to get things done as low cost as possible. When investing in servers, resources and overall business costs your project can soon turn into a financial disaster. Cloud solutions can help you in solving some financial problems, they can help you in scalability problems, and overall performance problems of your server or web application. Recently I moved the whole internal/external communication(email,calendar,documents) of my business to the cloud. I did this by using the free version of Google Apps. This works great and is a big advantage on multiple levels. I do not have to fight spam anymore on my system, and there are less resources used on my system. Also switching servers will go a lot easier. Questions Can you name some cloud solution that you have used, or some you just recommend. They can fairy form financial benefits, organizational benefits, performance benefits. It doesn't matter as soon as it helps you spread the load of your business.

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• What is the best VM for developing WPF apps from within OS X?

  - by MarqueIV

  All of my machines are Macs (Mac Pro, MacBook Pro, MacBook Air and Mac Mini (and Apple TV 2.0 too! :) ) but for my day-job, I develop .NET/WPF applications. Normally I just boot into Boot Camp and develop that way, which of course works great, but there are times when I need to simultaneously get to things on my Mac-side of the equation, so I've bought both VMware 3.1 and Parallels 6. Both work, however, even on my Mac Pro where I paid to upgrade to the better video cards (the NVidia 8600s I think vs. the stock ATI cards) the WPF performance bites!! Now this confuses me since both boast that they support not only hardware-accelerated OpenGL 2.1, but also hardware-accelerated DirectX 9 (VMware even allegedly supports DirectX 10!) via their respective virtual drivers and both can run 3D games just fine, even in a window. But even the simple act of resizing a WPF window that has a tiled background results in some HIDEOUS repainting and resizing behaviors. It's damn near closer to what you'd expect over RDP let alone a software-only renderer (forget accelerated hardware completely!) So... can anyone please tell me WTF WPF is doing differently? More importantly, how can I speed up the WPF performance? Should I switch to VirtualBox that also has support for DirectX? Or am I just gonna have to 'byte' the bullet (sorry... had to. So I like puns! Thank Jon Stewart!) and continue using Boot Camp?

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• Real benefits of tcp TIME-WAIT and implications in production environment

  - by user64204

  SOME THEORY I've been doing some reading on tcp TIME-WAIT (here and there) and what I read is that it's a value set to 2 x MSL (maximum segment life) which keeps a connection in the "connection table" for a while to guarantee that, "before your allowed to create a connection with the same tuple, all the packets belonging to previous incarnations of that tuple will be dead". Since segments received (apart from SYN under specific circumstances) while a connection is either in TIME-WAIT or no longer existing would be discarded, why not close the connection right away? Q1: Is it because there is less processing involved in dealing with segments from old connections and less processing to create a new connection on the same tuple when in TIME-WAIT (i.e. are there performance benefits)? If the above explanation doesn't stand, the only reason I see the TIME-WAIT being useful would be if a client sends a SYN for a connection before it sends remaining segments for an old connection on the same tuple in which case the receiver would re-open the connection but then get bad segments and and would have to terminate it. Q2: Is this analysis correct? Q3: Are there other benefits to using TIME-WAIT? SOME PRACTICE I've been looking at the munin graphs on a production server that I administrate. Here is one: As you can see there are more connections in TIME-WAIT than ESTABLISHED, around twice as many most of the time, on some occasions four times as many. Q4: Does this have an impact on performance? Q5: If so, is it wise/recommended to reduce the TIME-WAIT value (and what to)? Q6: Is this ratio of TIME-WAIT / ESTABLISHED connections normal? Could this be related to malicious connection attempts?

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• ZFS with L2ARC (SSD) slower for random seeks than without L2ARC

  - by Florian Kruse

  I am currently testing ZFS (Opensolaris 2009.06) in an older fileserver to evaluate its use for our needs. Our current setup is as follows: Dual core (2,4 GHz) with 4 GB RAM 3x SATA controller with 11 HDDs (250 GB) and one SSD (OCZ Vertex 2 100 GB) We want to evaluate the use of a L2ARC, so the current ZPOOL is: $ zpool status pool: tank state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM afstank ONLINE 0 0 0 raidz1 ONLINE 0 0 0 c11t0d0 ONLINE 0 0 0 c11t1d0 ONLINE 0 0 0 c11t2d0 ONLINE 0 0 0 c11t3d0 ONLINE 0 0 0 raidz1 ONLINE 0 0 0 c13t0d0 ONLINE 0 0 0 c13t1d0 ONLINE 0 0 0 c13t2d0 ONLINE 0 0 0 c13t3d0 ONLINE 0 0 0 cache c14t3d0 ONLINE 0 0 0 where c14t3d0 is the SSD (of course). We run IO tests with bonnie++ 1.03d, size is set to 200 GB (-s 200g) so that the test sample will never be completely in ARC/L2ARC. The results without SSD are (average values over several runs which show no differences) write_chr write_blk rewrite read_chr read_blk random seeks 101.998 kB/s 214.258 kB/s 96.673 kB/s 77.702 kB/s 254.695 kB/s 900 /s With SSD it becomes interesting. My assumption was that the results should be in worst case at least the same. While write/read/rewrite rates are not different, the random seek rate differs significantly between individual bonnie++ runs (between 188 /s and 1333 /s so far), average is 548 +- 200 /s, so below the value w/o SSD. So, my questions are mainly: Why do the random seek rates differ so much? If the seeks are really random, they should not differ much (my assumption). So, even if the SSD is impairing the performance it should be the same in each bonnie++ run. Why is the random seek performance worse in most of the bonnie++ runs? I would assume that some part of the bonnie++ data is in the L2ARC and random seeks on this data performs better while random seeks on other data just performs similarly like before.

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• HP Proliant DL380 G4 - Can this server still perform in 2011?

  - by BSchriver

  Can the HP Proliant DL380 G4 series server still perform at high a quality in the 2011 IT world? This may sound like a weird question but we are a very small company whose primary business is NOT IT related. So my IT dollars have to stretch a long way. I am in need of a good web and database server. The load and demand for a while will be fairly low so I am not looking nor do I have the money to buy a brand new HP Dl380 G7 series box for $6K. While searching around today I found a company in ATL that buys servers off business leases and then stripes them down to parts. They clean, check and test each part and then custom "rebuild" the server based on whatever specs you request. The interesting thing is they also provide a 3-year warranty on all their servers they sell. I am contemplating buying two of the following: HP Proliant DL380 G4 Dual (2) Intel Xeon 3.6 GHz 800Mhz 1MB Cache processors 8GB PC3200R ECC Memory 6 x 73GB U320 15K rpm SCSI drives Smart Array 6i Card Dual Power Supplies Plus the usual cdrom, dual nic, etc... All this for $750 each or $1500 for two pretty nicely equipped servers. The price then jumps up on the next model up which is the G5 series. It goes from $750 to like $2000 for a comparable server. I just do not have $4000 to buy two servers right now. So back to my original question, if I load Windows 2008 R2 Server and IIS 7 on one of the machines and Windows 2008 R2 server and MS SQL 2008 R2 Server on another machine, what kind of performance might I expect to see from these machines? The facts is this series is now 3 versions behind the G7's and this series of server was built when Windows 200 Server was the dominant OS and Windows 2003 Server was just coming out. If you are running Windows 2008 R2 Server on a G4 with similar or less specs I would love to hear what your performance is like.

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• Caching all files in varnish

  - by csgwro

  I want my varnish servers to cache all files. At backend there is lighttpd hosting only static files, and there is an md5 in the url in case of file change, ex. /gfx/Bird.b6e0bc2d6cbb7dfe1a52bc45dd2b05c4.swf). However my hit ratio is very poorly (about 0.18) My config: sub vcl_recv { set req.backend=default; ### passing health to backend if (req.url ~ "^/health.html$") { return (pass); } remove req.http.If-None-Match; remove req.http.cookie; remove req.http.authenticate; if (req.request == "GET") { return (lookup); } } sub vcl_fetch { ### do not cache wrong codes if (beresp.status == 404 || beresp.status >= 500) { set beresp.ttl = 0s; } remove beresp.http.Etag; remove beresp.http.Last-Modified; } sub vcl_deliver { set resp.http.expires = "Thu, 31 Dec 2037 23:55:55 GMT"; } I have made an performance tuning: DAEMON_OPTS="${DAEMON_OPTS} -p thread_pool_min=200 -p thread_pool_max=4000 -p thread_pool_add_delay=2 -p session_linger=100" The main url which is missed is... /health.html. Is that forward to backend correctly configured? Disabling health checking hit ratio increases to 0.45. Now mostly "/crossdomain.xml" is missed (from many domains, as it is wildcard). How can I avoid that? Should I carry on other headers like User-Agent or Accept-Encoding? I thing that default hashing mechanism is using url + host/IP. Compression is used at the backend. What else can improve performance?

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• Server slowdown

  - by Clinton Bosch

  I have a GWT application running on Tomcat on a cloud linux(Ubuntu) server, recently I released a new version of the application and suddenly my server response times have gone from 500ms average to 15s average. I have run every monitoring tool I know. iostat says my disks are 0.03% utilised mysqltuner.pl says I am OK other see below top says my processor is 99% idle and load average: 0.20, 0.31, 0.33 memory usage is 50% (-/+ buffers/cache: 3997 3974) mysqltuner output [OK] Logged in using credentials from debian maintenance account. -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.63-0ubuntu0.10.04.1-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 370M (Tables: 52) [--] Data in InnoDB tables: 697M (Tables: 1749) [!!] Total fragmented tables: 1754 -------- Security Recommendations ------------------------------------------- [OK] All database users have passwords assigned -------- Performance Metrics ------------------------------------------------- [--] Up for: 19h 25m 41s (1M q [28.122 qps], 1K conn, TX: 2B, RX: 1B) [--] Reads / Writes: 98% / 2% [--] Total buffers: 1.0G global + 2.7M per thread (500 max threads) [OK] Maximum possible memory usage: 2.4G (30% of installed RAM) [OK] Slow queries: 0% (1/1M) [OK] Highest usage of available connections: 34% (173/500) [OK] Key buffer size / total MyISAM indexes: 16.0M/279.0K [OK] Key buffer hit rate: 99.9% (50K cached / 40 reads) [OK] Query cache efficiency: 61.4% (844K cached / 1M selects) [!!] Query cache prunes per day: 553779 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 34K sorts) [OK] Temporary tables created on disk: 4% (4K on disk / 102K total) [OK] Thread cache hit rate: 84% (185 created / 1K connections) [!!] Table cache hit rate: 0% (256 open / 27K opened) [OK] Open file limit used: 0% (20/2K) [OK] Table locks acquired immediately: 100% (692K immediate / 692K locks) [OK] InnoDB data size / buffer pool: 697.2M/1.0G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Enable the slow query log to troubleshoot bad queries Increase table_cache gradually to avoid file descriptor limits Variables to adjust: query_cache_size (> 16M) table_cache (> 256)

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• Why database partitioning didn't work? Extract from thedailywtf.com

  - by questzen

  Original link. http://thedailywtf.com/Articles/The-Certified-DBA.aspx. Article summary: The DBA suggests an approach involving rigorous partitioning, 10 partitions per disk (3 actual disks and 3 raid). The stats show that the performance is non-optimal. Then the DBA suggests an alternative of 1 partition per disk (with more added disks). This also fails. The sys-admin then sets up a single disk, single partition and saves the day. The size of disks was not mentioned but given today,s typical disk sizes (of the order of 100 GB), the partitions ; would be huge, it surprises me that a single disk with all partitions outperformed. Initially I suspect that the data was segregated and hence faster reads. But how come the performance didn't degrade as time went by with all the inserts and updates happening? Saw this on reddit, but the explanation was by far spindle/platter centered. There was no mention in the article about this. Is there any other reason? I can only guess that the tables were using a incorrect hash distribution causing non-uniform allocation across disks (wrong partitioning); this would increase fetch times. Any thoughts?

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