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  • Performance affects of compressing Program Files on Windows / NTFS

    - by SRobertJames
    What are the performance affects of compressing Program Files on Windows NTFS? On a fast, multicore machine, the overhead of decompression is minimal. Machines are generally disk bound, and if you can reduce the disk load by compression, you often speed things up. (Microsoft says that the built in compression of Windows Search indexes actually improves speed for this reason.) On the other hand, Windows' virtual memory is complicated. Perhaps if files are compressed, they can't be paged out simply. And there may be other issues. In short: On a fast, multicore machine with a relatively slow disk, what performance affects will compressing Program Files have?

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  • General video performance affected on Mac OSX 10.5 (PowerBook G4)

    - by r0ca
    Hi all, I'm quite new to Mac and I just got a PowerBook G4 for free. I installed OSX 10.5 on it and for the first two weeks, everything was going kinda smooth even if this is similar to a P3. I'm not expecting awsome video performance but at least be able to watch some videos from Youtube. Yesterday night, I installed Office 2008 for mac and this morning, even after a reboot, my computer is way much slower that I used to know. I watched a youtube video and the framerate was 1:1. I also noticed it on flash adds, it's way slower! Is there anything that I can do to increase video performance, see what's the process list running and taking more GPU or CPU, what's taking more ram and stuff like that?! What do you guys, Mac pros, would do on an old laptop with OSX 10.5 Thanks!

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  • Verify server performance

    - by George Kesler
    I'm looking for a quick and SIMPLE way to verify that new servers are performing as expected. The most important metric is disk performance, second is network performance. I’m trying to prevent problems caused by misconfiguration of RAID arrays, NIC teaming etc. The solution should work with both physical and virtual servers. I don’t need sophisticated analysis with different workloads, just one set of benchmarks which I would run against a reference server and later compare to new ones. One problem is that most benchmarks are not giving accurate results when running on a VM.

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  • Analyzing Linux NFS server performance

    - by Kamil Kisiel
    I'd like to do some analysis of our NFS server to help track down potential bottlenecks in our applications. The server is running SUSE Enterprise Linux 10. The kind of things I'm looking to know are: Which files are being accessed by which clients Read/write throughput on a per-client basis Overhead imposed by other RPC calls Time spent waiting on other NFS requests, or disk I/O, to service a client I already know about the statistics available in /proc/net/rpc/nfsd and in fact I wrote a blog post describing them in depth. What I'm looking for is a way to dig deeper and help understand what factors are contributing to the performance seen by a particular client. I want to analyze the role the NFS server plays in the performance of an application on our cluster so that I can think of ways to best optimize it.

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  • RAID10 without write-back cache = horrible write performance?

    - by Harry Mexican
    I have just provisioned a dedicated server on singlehop. I'm running it through some tests to know what to expect performance-wise. On the I/O side (with 4 1TB disks in RAID 10) I get: write-cache disabled 200 MB/s read throughput 30 MB/s write throughput I thought that was really low compared to my desktop HD which gets 150-150 or so. So I had a chat with them and they suggested enabling the write cache. New results: write-cache enabled 280 MB/s read 260 MB/s write which is great and all but means I'd have to add a BBU for an additional monthly cost. Is it normal for the write throughput to be 1/4 of a regular drive on RAID10, if you don't have write cache? It almost feels like its intentionally bad to force you to pony up for the BBU. I'd be happy with normal non-raid performance of 150/150.

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  • performance block countries using iptables /netfilter

    - by markus
    It's easy to block IPs from country using iptables (e.g. like http://www.cyberciti.biz/faq/block-entier-country-using-iptables/). However I read that the performance can go down if the deny list get too large. An alternative is installing the iptables geoip patch or using ipset ( http://www.jsimmons.co.uk/2010/06/08/using-ipset-with-iptables-in-ubuntu-lts-1004-to-block-large-ip-ranges/) instead of iptables. Does anyone have experience with the various approaches and can say something about the performance differences ? Are there are other ways to block country IPs in linux which I did't mentioned above?

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  • Determining Performance Limits

    - by JeffV
    I have a number of windows processes that pass messages between them hat a high rate using tcp to local host. Aside from testing on actual hardware how can I assess what my hardware limit will be. These applications are not doing CPU intensive work, mostly decomposing and combining messages, scanning over them for special flag in the data etc.. The message size is typically 3k and the rate is typically ~10k messages per second. ~30MB per second between processing stages. There may be 10 or more stages depending. For this type of application, what should I look to for assessing performance? What do I look for in a server performance wise? I am currently running an XEON L5408 with 32 GB ram. But I am assuming cache is more important than actual ram size as I am barely touching the ram.

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  • Does shutdown idle VMs improve the performance?

    - by Samselvaprabu
    Often our team members are coming to me with a compliant that their VMs are slow. Our team members suggested to shutdown some of the VMs temporarily and try to access the VM. But most cases that would not help. Assume that i have assigned 4 GB for and 2 CPUs for my VM. So ideally it should not face performance issue. As our ESXi 4.1 server has multiple VM in the same server (we have overcommited memory and CPU). Does shut down other VM really helps to improve performance or not? [Note : We are using ESXi 4.1 and our hardware is R710 server. We have more number of VMs in single server so we have overcommited memory.]

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  • Strange performance from RAID5 using WD RE4 disks

    - by Howard
    I've noticed a bit of a performance issue with some WD RE4 drives I'm using under AMD's hardware RAID solution. First a bit of background: Environment: Windows 7 home premium x64 HDD's: 3x 1TB WD Raid Edition 4 in a RAID 5 setup with 128 kbyte stripe (2TB usable space) Testing Tool: HD Tune, process set to "High Priority" Processor: AMD Phenom II x6 1100T Ram: 16GB DDR3/1600mhz Motherboard: MSI 970A-G45 The image below pretty much depicts the issue I'm having. Every test has the same thing, a period of similar length where the performance drops to a few megabytes a second. This can't be a TLER issue as the purpose of RE4's is to work around that. Any help would be greatly appreciated.

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  • OBIEE 11.1.1 - (Updated) Best Practices Guide for Tuning Oracle® Business Intelligence Enterprise Edition (Whitepaper)

    - by Ahmed Awan
    Applies To: This whitepaper applies to OBIEE release 11.1.1.3, 11.1.1.5 and 11.1.1.6 Introduction: One of the most challenging aspects of performance tuning is knowing where to begin. To maximize Oracle® Business Intelligence Enterprise Edition performance, you need to monitor, analyze, and tune all the Fusion Middleware / BI components. This guide describes the tools that you can use to monitor performance and the techniques for optimizing the performance of Oracle® Business Intelligence Enterprise Edition components. Click to Download the OBIEE Infrastructure Tuning Whitepaper (Right click or option-click the link and choose "Save As..." to download this file) Disclaimer: All tuning information stated in this guide is only for orientation, every modification has to be tested and its impact should be monitored and analyzed. Before implementing any of the tuning settings, it is recommended to carry out end to end performance testing that will also include to obtain baseline performance data for the default configurations, make incremental changes to the tuning settings and then collect performance data. Otherwise it may worse the system performance.

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  • jQuery Selector Tester and Cheat Sheet

    - by SGWellens
    I've always appreciated these tools: Expresso and XPath Builder. They make designing regular expressions and XPath selectors almost fun! Did I say fun? I meant less painful. Being able to paste/load text and then interactively play with the search criteria is infinitely better than the code/compile/run/test cycle. It's faster and you get a much better feel for how the expressions work. So, I decided to make my own interactive tool to test jQuery selectors:  jQuery Selector Tester.   Here's a sneak peek: Note: There are some existing tools you may like better: http://www.woods.iki.fi/interactive-jquery-tester.html http://www.w3schools.com/jquery/trysel.asp?filename=trysel_basic&jqsel=p.intro,%23choose My tool is different: It is one page. You can save it and run it locally without a Web Server. It shows the results as a list of iterated objects instead of highlighted html. A cheat sheet is on the same page as the tester which is handy. I couldn't upload an .htm or .html file to this site so I hosted it on my personal site here: jQuery Selector Tester. Design Highlights: To make the interactive search work, I added a hidden div to the page: <!--Hidden div holds DOM elements for jQuery to search--><div id="HiddenDiv" style="display: none"></div> When ready to search, the searchable html text is copied into the hidden div…this renders the DOM tree in the hidden div: // get the html to search, insert it to the hidden divvar Html = $("#TextAreaHTML").val();$("#HiddenDiv").html(Html); When doing a search, I modify the search pattern to look only in the HiddenDiv. To do that, I put a space between the patterns.  The space is the Ancestor operator (see the Cheat Sheet): // modify search string to only search in our// hidden div and do the searchvar SearchString = "#HiddenDiv " + SearchPattern;try{    var $FoundItems = $(SearchString);}   Big Fat Stinking Faux Pas: I was about to publish this article when I made a big mistake: I tested the tool with Mozilla FireFox. It blowed up…it blowed up real good. In the past I’ve only had to target IE so this was quite a revelation. When I started to learn JavaScript, I was disgusted to see all the browser dependent code. Who wants to spend their time testing against different browsers and versions of browsers? Adding a bunch of ‘if-else’ code is a tedious and thankless task. I avoided client code as much as I could. Then jQuery came along and all was good. It was browser independent and freed us from the tedium of worrying about version N of the Acme browser. Right? Wrong! I had used outerHTML to display the selected elements. The problem is Mozilla FireFox doesn’t implement outerHTML. I replaced this: // encode the html markupvar OuterHtml = $('<div/>').text(this.outerHTML).html(); With this: // encode the html markupvar Html = $('<div>').append(this).html();var OuterHtml = $('<div/>').text(Html).html(); Another problem was that Mozilla FireFox doesn’t implement srcElement. I replaced this: var Row = e.srcElement.parentNode;  With this: var Row = e.target.parentNode; Another problem was the indexing. The browsers have different ways of indexing. I replaced this: // this cell has the search pattern  var Cell = Row.childNodes[1];   // put the pattern in the search box and search                    $("#TextSearchPattern").val(Cell.innerText);  With this: // get the correct cell and the text in the cell// place the text in the seach box and serachvar Cell = $(Row).find("TD:nth-child(2)");var CellText = Cell.text();$("#TextSearchPattern").val(CellText);   So much for the myth of browser independence. Was I overly optimistic and gullible? I don’t think so. And when I get my millions from the deposed Nigerian prince I sent money to, you’ll see that having faith is not futile. Notes: My goal was to have a single standalone file. I tried to keep the features and CSS to a minimum–adding only enough to make it useful and visually pleasing. When testing, I often thought there was a problem with the jQuery selector. Invariable it was invalid html code. If your results aren't what you expect, don't assume it's the jQuery selector pattern: The html may be invalid. To help in development and testing, I added a double-click handler to the rows in the Cheat Sheet table. If you double-click a row, the search pattern is put in the search box, a search is performed and the page is scrolled so you can see the results. I left the test html and code in the page. If you are using a CDN (non-local) version of the jQuery libraray, the designer in Visual Studio becomes extremely slow.  That's why there are two version of the library in the header and one is commented out. For reference, here is the jQuery documentation on selectors: http://api.jquery.com/category/selectors/ Here is a much more comprehensive list of CSS selectors (which jQuery uses): http://www.w3.org/TR/CSS2/selector.html I hope someone finds this useful. Steve WellensCodeProject

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  • Why does Chrome video performance substantially degrade after waking from suspend in 10.10?

    - by Grant Heaslip
    Note: For some more details, some of which may not be true given what I've figured out, see this post. When I first boot my computer, video performance (both native H.264 HTML5 in YouTube and Vimeo, and in Flash) in Chrome is perfectly reasonable. CPU usage stays slow, everything works correctly, and the video is silky-smooth. But for whatever reason, if I suspend my computer then wake it up, video performance plummets. Full screen HTML5 video is choppy at best, and full-screen Flash video basically brings my computer to its knees (I'm talking less than a frame a second, and a 5 second lead time to leave full-screen after hitting Esc). Restarting Chrome doesn't fix this — I need to completely restart my machine before performance goes back to normal. Video performance in other applications, such as Movie Player, doesn't seem to be affected at all by the suspend cycle — it's only Chrome. I'm using a Lenovo X201, with an Intel GMA HD graphics chipset, and Intel compnents all around (I don't need any proprietary drivers). This didn't happen in 10.04, and I haven't anything that I think would have caused this to happen. It's possible that a Chrome release could have caused this, but it seems less likely than a regression between 10.04 and 10.10. Any ideas? EDIT: In response Georg's comment, logging in and out doesn't fix it. Restarting Compiz or switching to Metacity (at least by using "compiz/metacity --replace & disown" — am I doing it right?) doesn't help (actually, it seemed to help somewhat with Flash once, but I haven't been able to reproduce this). I'm not sure about GDM — when I use "sudo restart gdm" I get kicked back to the Linux shell (?), which I have no idea how to get out of. Also, I want to make very clear that this isn't just a case of Flash sucking (it does,but that's beside the point). I"m seeing the same general problem with HTML5 videos, and Flash is performing better on my Nexus One than it does on my Core i5 laptop. There's something screwy going on with Chrome and/or 10.10.

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  • How can I filter using the current value of a text box in a jQuery selector?

    - by spudly
    I have a validation script that checks for data-* attributes to determine which fields are required. If an element has the 'data-required-if' attribute (which has a jQuery selector as it's value), it checks to see if any elements are found that match that selector. If any are found, the field is required. It does something similar to the following: $('[data-required-if]').each(function () { var selector = $(this).attr('data-required-if'), required = false; if ( !$(selector).length ) { required = true; // do something if this element is empty } }); This works great, but there's a problem. When you use the attribute selector to filter based on the current value of a text field, it really filters on the initial value of the text field. <input type='text' id='myinput' value='initial text' /> <input type='text' id='dependent_input' value='' data-required-if="#myinput[value='']" /> // Step 1: type "foobar" in #myinput // Step 2: run these lines of code: <script> $('#myinput').val() //=> returns "foobar" $('#myinput[value="foobar"]').length //=> returns 0 </script> I understand why it's doing that. jQuery probably uses getAttribute() in the background. Is there any other way to filter based on the current value of an input box using purely jQuery selectors?

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  • Getting Optimal Performance from Oracle E-Business Suite

    - by Steven Chan (Oracle Development)
    Performance tuning and optimization in E-Business Suite environments can involve many different components and diagnostic tools.  Samer Barakat, Senior Architect in our Applications Performance group, held an OpenWorld 2013 session that covered: Performance triage, analysis and diagnostic tools Optimizing the E-Business Suite application tier, including Concurrent Manager Optimizing the E-Business Suite database tier Optimizing the E-Business Suite on Real Application Clusters (RAC) E-Business Suite on engineered systems, including Exadata and Exalogic Optimizing E-Business Suite data management, including archiving and purging  The Applications Performance group works with the world's largest E-Business Suite customers to isolate and resolve performance bottlenecks. This team has helped tune the E-Business Suite environments of world's largest companies to handle staggering amounts of transactional volume in multi-terabyte databases.  This group also publishes our official Oracle Apps benchmarks, white papers, and performance metrics. This is an essential set of tips and techniques that all EBS sysadmins and DBAs can use to improve the performance of their environments: Getting Optimal Performance from Oracle E-Business Suite (PDF, 1.7 MB) OpenWorld 2013 presentations are only available for approximately six months -- until ~March 2013.  Download this one while it's still available. Related Articles E-Business Suite Technology Sessions at OpenWorld 2013 OAUG/Collaborate Recap: Best Practices for E-Business Suite Performance Tuning

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  • Bad disk performance on HP DL360 with Smarty Array P400i RAID controller

    - by sarge
    I have a HP DL360 server with 4x 146GB SAS disks and a Smart Array P400i RAID controller with 256MB cache. The disks are in RAID 5 (3 disks + 1 hot spare). The server is running VMware ESX 3i. The disk write performance is really bad. Here are some numbers: ns1:~# hdparm -tT /dev/sda /dev/sda: Timing cached reads: 3364 MB in 2.00 seconds = 1685.69 MB/sec Timing buffered disk reads: 18 MB in 3.79 seconds = 4.75 MB/sec ns1:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=125000 && sync" 125000+0 records in 125000+0 records out 1024000000 bytes (1.0 GB) copied, 282.307 s, 3.6 MB/s real 4m52.003s user 0m2.160s sys 3m10.796s Compared to another server those number are terrible: Dell R200, 2x 500GB SATA disks, PERC raid controller (disks are mirrored). web4:~# hdparm -tT /dev/sda /dev/sda: Timing cached reads: 6584 MB in 2.00 seconds = 3297.79 MB/sec Timing buffered disk reads: 316 MB in 3.02 seconds = 104.79 MB/sec web4:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=125000 && sync" 125000+0 records in 125000+0 records out 1024000000 bytes (1.0 GB) copied, 35.2919 s, 29.0 MB/s real 0m36.570s user 0m0.476s sys 0m32.298s The server isn't very loaded and the VMware Infrastructure Client performance monitor is showing 550KBps average read and 1208KBps average write for the last 30 minutes (highest write rate: 6.6MBps). This has been a problem from the start. Any ideas?

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  • Performance variation

    - by Ree
    During my time spent working with multiple machines, I have noticed that performance of the same machine doing the same tasks in the same order differs and sometimes the difference is big enough to be noticeable. This applies to all the machines I've owned and/or maintained (old and modern). Some examples (many of them you may have noticed yourself) that sometimes are completed in different time frames: POST OS installation Hardware tests and operations (usually executed within a customized OS such as one of the many DOS variants), HDD tests and "low level" formats Software installation or other tasks (such as benchmarks) within a general purpose OS (Windows, Linux, etc) I can imagine this is caused by the fact that a machine is built with many components having to communicate as a whole and since the mechanical and electronic parts aren't perfect the overhead occurs. In the last example, I assume the OS complexity and concurrently running multiple processes has some additional effect as well. However, I'm wondering if this hardware imperfection and overhead is indeed that high to be humanly noticeable? Maybe there are other factors that are influencial as much or even more? So, in short - why? To emphasize: the difference is noticeable on the same machine performing the same tasks and this applies to ANY machine in my experience. I'm not comparing machine to machine performance.

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  • Improving Performance of RDP Over LAN

    - by Jared Brown
    Architecture: A deployment of 6 new HP thin clients (Windows XP Embedded) with TCP/IP access to several new HP servers (Windows 2003 Server). Each thin client is connected over fiber optic to a Gigabit Cisco switch, which the servers are connected to. There are 10/100 Ethernet to fiber converter boxes on each end of the fiber cables. Problem: Noticeable lag over RDP while using the Unigraphics CAD package. 3D models take .5 to 1 second to respond to mouse actions. Other Details: Network throughput on each thin client's RDP session is 7288 kbps. RDP connection settings - color setting: 15k, all themes, etc. turned off. Local and remote system performance stats are well within norms (CPU, Memory, and Network). Question: Are there newer versions of terminal services or RDP I can use on my existing OSes? Are there compression algorithms, etc. that are well suited for a high-bandwidth LAN? Are there valid alternatives that will yield higher performance (i.e. UltraVNC with drivers installed)? Are there TCP/IP tuning options I can exploit?

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  • Low CPU performance with low usage and clock - Windows 8.1

    - by Daniele
    I recently deleted everything from my PC and reinstalled Windows 8.1 from scratch. When I first booted into Windows everything was extremely slow though the CPU usage was very low (about 1%). After installing some drivers the problem seemed to be solved, I was able to use my PC normally. Today I installed a game and I noticed a strange behavior: the game was playable but the performance worsened more and more in the time. This is the situation BEFORE opening the game (normal): This is AFTER some minutes inside the game (low CPU usage and clock): Some information about my system: PC: Sony Vaio S13 (SVS13A1C5E) OS: Windows 8.1 CPU: Intel Core i7-3520M 2.90GHz GPU(1): Intel HD Graphics 4000 GPU(2): NVIDIA GeForce GT 640M LE I tried searching for new drivers and other solutions but noting worked and I don't know what is the cause. I did not checked the temperatures but the fans are not running fast and the PC does not look overheated. Update: Max CPU Temp: 66°C, Max GPU Temp: 61°C The strange thing is that the GPU load is 99% (GPU-Z) and the fan is almost silent. Update 2: I had troubles with Sony Vaio software, I can't get the FN keys and the STAMINA/SPEED switch to work (it is a physical switch to enable/disable the Nvidia card and change the Power Profile). I'm saying this because I remember that before reinstalling Windows there was an option in the Vaio Control Center (now it is not there anymore) that allowed me to choose from something like "priority to performance (ventilation)" or "priority to silence". The current behavior looks like a "priority to silence", but I can't get the stamina-speed switch to work and so I don't see similar oprions in the Vaio Control Center. I don't know if the problem is related to this.

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  • Linux Kernel Packet Forwarding Performance

    - by Bob Somers
    I've been using a Linux box as a router for some time now. Nothing too fancy, just enabling forwarding in the kernel, turning on masquerading, and setting up iptables to poke a few holes in the firewall. Recently a friend of mine pointed out a performance problem. Single TCP connections seem to experience very poor performance. You have to open multiple parallel TCP connections to get decent speed. For example, I have a 10 Mbit internet connection. When I download a file from a known-fast source using something like the DownThemAll! extension for Firefox (which opens multiple parallel TCP connections) I can get it to max out my downstream bandwidth at around 1 MB/s. However, when I download the same file using the built-in download manager in Firefox (uses only a single TCP connection) it starts fast and the speed tanks until it tops out around 100 KB/s to 350 KB/s. I've checked the internal network and it doesn't seem to have any problems. Everything goes through a 100 Mbit switch. I've also run iperf both internally (from the router to my desktop) and externally (from my desktop to a Linux box I own out on the net) and haven't seen any problems. It tops out around 1 MB/s like it should. Speedtest.net also reports 10 Mbits speeds. The load on the Linux machine is around 0.00, 0.00, 0.00 all the time, and it's got plenty of free RAM. It's an older laptop with a Pentium M 1.6 GHz processor and 1 GB of RAM. The internal network is connected to the built in Intel NIC and the cable modem is connected to a Netgear FA511 32-bit PCMCIA network card. I think the problem is with the packet forwarding in the router, but I honestly am not sure where the problem could be. Is there anything that would substantially slow down a single TCP stream?

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  • PHP/MySQL Performance Testing with Just PHP

    - by Mike Gifford
    I'm trying to diagnose a server where the website is loading very slowly, but unfortunately my client has only provided me with FTP access. I've got FTP access so I can upload PHP scripts, but can't set up any other server side tools. I have access to phpMyAdmin, but not direct access to the MySQL server. It is also unfortunately a Windows server (and we've been a Linux shop for over a decade now). So, if I wan to evaluate MySQL & disk speed performance through PHP on a generic server, what is the best way to do this? There are already tools like: https://github.com/raphaelm/php-benchmark or https://github.com/InfinitySoft/php-benchmark But I'm surprised there isn't something that someone has already set up & configured to just run through and do some basic testing of a server's responsiveness. Every time we evaluate a new server environment it's handy to be able to compare it to an existing one quickly to see if there are any anomalies. I guess I'd just hoped that someone else had written up a script to do this already. I know I have, but that was before Github when there was a handy place to post scraps of code like this. Originally posted in http://stackoverflow.com/questions/12321498/php-mysql-performance-testing-with-just-php but it was recommended that I re-post it here.

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  • IIS High use & Server Performance issues

    - by HaydnWVN
    Have an SBS2011 running Exchange, a database app and a few other things serving 5 users (3 low use, 1 high). The server was never specced for the database app so it isn't as powerful as I'd like... Only 12GB RAM. We have increasingly found performance problems with this server, last week it was so bad I couldn't even connect remotely. To free up some available RAM I have (over the past month or so): Restricted the Exchange Message Store to 1GB with (so far) no ill effects. Restricted SQL Databases (including SBSMonitoring and Sharepoint/##SSEE (Which isn't used)). Now I am finding that IIS Worker threads are using up the available memory and I have (so far) been unable to track down much useful information about restricting them. This server is not 'serving' anything web-based apart from OWA that I am finding people using because Outlook is so slow (again related to the Servers performance). I am aware that Exchange on SBS2011 is designed to use up available resources (and concede when other applications request). But it is not doing so (or anywhere near fast enough) for our needs. Opening the database application (using Postgres) takes 5+ minutes from client machines and regularly times out or crashes due to this. After a reboot (before SQL/Exchange/IIS databases are very large/totally cached) we get the performace we need and expect. Previously a reboot once a month was enough... Then once a week... Now they have taken to rebooting it almost daily!

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  • Very slow write performance on Debian 6.0 (AMD64) with DMCRYPT/LVM/RAID1

    - by jdelic
    I'm seeing very strange performance characteristics on one of my servers. This server is running a simple two-disk software-RAID1 setup with LVM spanning /dev/md0. One of the logical volumes /dev/vg0/secure is encrypted using dmcrypt with LUKS and mounted with the sync and noatimes flag. Writing to that volume is incredibly slow at 1.8 MB/s and the CPU usage stays near 0%. There are 8 crpyto/1-8 processes running (it's a Intel Quadcore CPU). I hope that someone on serverfault has seen this before :-(. uname -a 2.6.32-5-xen-amd64 #1 SMP Tue Mar 8 00:01:30 UTC 2011 x86_64 GNU/Linux Interestingly, when I read from the device I get good performance numbers: reading without encryption: $ dd if=/dev/vg0/secure of=/dev/null bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes (6.6 GB) copied, 68.8951 s, 95.1 MB/s reading with encryption: $ dd if=/dev/mapper/secure of=/dev/null bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes (6.6 GB) copied, 69.7116 s, 94.0 MB/s However, when I try to write to the device: $ dd if=/dev/zero of=./test bs=64k 8809+0 records in 8809+0 records out 577306624 bytes (577 MB) copied, 321.861 s, 1.8 MB/s Also, when I read I see CPU usage, when I write, the CPU stays at almost 0% usage. Here is output of cryptsetup luksDump: LUKS header information for /dev/vg0/secure Version: 1 Cipher name: aes Cipher mode: cbc-essiv:sha256 Hash spec: sha1 Payload offset: 2056 MK bits: 256 MK digest: dd 62 b9 a5 bf 6c ec 23 36 22 92 4c 39 f8 d6 5d c1 3a b7 37 MK salt: cc 2e b3 d9 fb e3 86 a1 bb ab eb 9d 65 df b3 dd d9 6b f4 49 de 8f 85 7d 3b 1c 90 83 5d b2 87 e2 MK iterations: 44500 UUID: a7c9af61-d9f0-4d3f-b422-dddf16250c33 Key Slot 0: ENABLED Iterations: 178282 Salt: 60 24 cb be 5c 51 9f b4 85 64 3d f8 07 22 54 d4 1a 5f 4c bc 4b 82 76 48 d8 a2 d2 6a ee 13 d7 5d Key material offset: 8 AF stripes: 4000 Key Slot 1: DISABLED Key Slot 2: DISABLED Key Slot 3: DISABLED Key Slot 4: DISABLED Key Slot 5: DISABLED Key Slot 6: DISABLED Key Slot 7: DISABLED

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  • How to configure VirtualBox server for performance at home

    - by BluJai
    I currently have two physical Ubuntu Server 10.10 servers at home: one serves as our firewall/router/DHCP/VPN server and the other performs double-duty as a file server and a VirtualBox host for an Ubuntu Desktop 10.10 machine which I use from remote connections (via NoMachine) for many thin-client purposes which are irrelevant to my question. What I'd like to accomplish is to consolidate the two physical machines into one which is a dedicated VirtualBox host (most likely running Ubuntu Server 10.10). Note that I'd like to stick with VirtualBox (if possible) because I'm most comfortable with it and use it on a daily basis at both home and work. Specifically, I plan to have one VM set up as file server, another as the firewall/router/DHCP/VPN (or possibly split those a bit) and a third, which is the only current VM (already VirtualBox), which is the thin-client host. My question comes down to performance and/or recommendations about the file server VM. The file server hosts about 6 terabytes of data across 4 drives. What I'd like to do is use raw disk access from the VM directly to the existing disks. However, I'm curious what performance advantage/disadvantage that would have as compared to using shared folders from the VM host and basically just have the whole drive served as a shared folder to the VM which would then serve it to the other machines on the network. I don't know if virtual disks would even work in this scenario and I certainly wouldn't want a drive to be filled with just a single file which is 1.5 TB (disk image). To add understanding of context, but not to get additional advice, I want to virtualize these machines because I intend to regularly use the snapshot capabilities of VirtualBox for the system disks (which will be virtual drives) of the VMs and I have some physical space/power needs to address (as I mentioned, this is at home).

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