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  • How to correctly partition usb flash drive and which filesystem to choose considering wear leveling?

    - by random1
    Two problems. First one: how to partition the flash drive? I shouldn't need to do this, but I'm no longer sure if my partition is properly aligned since I was forced to delete and create a new partition table after gparted complained when I tried to format the drive from FAT to ext4. The naive answer would be to say "just use default and everything is going to be alright". However if you read the following links you'll know things are not that simple: https://lwn.net/Articles/428584/ and http://linux-howto-guide.blogspot.com/2009/10/increase-usb-flash-drive-write-speed.html Then there is also the issue of cylinders, heads and sectors. Currently I get this: $sfdisk -l -uM /dev/sdd Disk /dev/sdd: 30147 cylinders, 64 heads, 32 sectors/track Warning: The partition table looks like it was made for C/H/S=*/255/63 (instead of 30147/64/32). For this listing I'll assume that geometry. Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End MiB #blocks Id System /dev/sdd1 1 30146 30146 30869504 83 Linux $fdisk -l /dev/sdd Disk /dev/sdd: 31.6 GB, 31611420672 bytes 255 heads, 63 sectors/track, 3843 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: 0x00010c28 So from my current understanding I should align partitions at 4 MiB (currently it's at 1 MiB). But I still don't know how to set the heads and sectors properly for my device. Second problem: file system. From the benchmarks I saw ext4 provides the best performance, however there is the issue of wear leveling. How can I know that my Transcend JetFlash 700's microcontroller provides for wear leveling? Or will I just be killing my drive faster? I've seen a lot of posts on the web saying don't worry the newer drives already take care of that. But I've never seen a single piece of backed evidence of that and at some point people start mixing SSD with USB flash drives technology. The safe option would be to go for ext2, however a serious of tests that I performed showed horrible performance!!! These values are from a real scenario and not some synthetic test: 42 files: 3,429,415,284 bytes copied to flash drive original fat32: 15.1 MiB/s ext4 after new partition table: 10.2 MiB/s ext2 after new partition table: 1.9 MiB/s Please read the links that I posted above before answering. I would also be interested in answers backed up with some references because a lot is said and re-said but then it lacks facts. Thank you for the help.

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  • is there anyway to know if your supposedly fully dedicated server is really a virtually resource-sha

    - by siran
    Hi, sometimes I feel my server not responding as smoothly as I would expect (i have a Intel(R) Xeon(TM) CPU 2.80GHz Quad Core), given that for example, the 'top' commands reports a low load < 0.5, CPU are almost completely idle ... I maybe have internet connectivity issues, so I don't really know if it's me or if it's the server itself. Is there anykind of benchmarking script (or something analogous) I could run and see the actual performance of the server ?

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  • SAS Array with or without expander

    - by tegbains
    Is it better to use a SAS Expander backplane for 12 drives via one SAS connection or is it better to use a SAS backplane with 3 SAS connections? This is in terms of performance, rather than expansion. This array will be setup using ZFS on a OpenSolaris via a LSI SAS controller as an iSCSI target. The two products being considered are the SuperMicro SuperChassis 826A-R1200LPB or the SuperChassis 826E2-R800LPB

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  • Speed of TrueCrypt whole disk encryption

    - by Gareth
    I'm getting a new development laptop soon, and I'm thinking of using TrueCrypt to encrypt the whole disk. What kind of performance drop can I expect? 10%? 30%? more? Also, assuming the workload has an effect, would compiling/using Visual Studio be affected much? I cannot seem to find anything like this on the web.

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  • Any reason not to disable Windows kernel paging?

    - by Nathaniel
    So I'm planning on eventually going to 2 GB (mobo max) RAM from 1 GB, and I want to disable kernel paging once I do, because I've heard it can give a performance boost (and that I believe). Any reason not to do it or any general thoughts about it? Edit: for clarification, this is not disabling general RAM paging. This is disabling having kernel memory paged (or at least parts of it, as Charlls noted).

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  • How to monitor the total number of SQL Server logins

    - by Shiraz Bhaiji
    We have an SQL Server 2005 that is the backend of a web application. The application is partly SharePoint and partly web services accessing the database via Entity Framework. In the performance monitor I am seeing average SQL Logins is ca, 60 per second (max 170), but the average logouts is less than 1. Where can I see the total number of SQL Server logins? Anyone have an idea what could be causing this?

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  • Why are there many processes listed under the same title in htop?

    - by javanix
    Can anyone explain to me why there are sometimes 10 or 15 processes with the same title and "stats" listed in htop? I'm guessing there are multiple threads running - but that many of them obviously couldn't be running concurrently. Is there any sort of performance hit taken if a process uses say, 15 non-concurrent threads vs. 10 non-concurrent threads?

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  • Why is my new Phenom II 965 BE not significantly faster than my old Athlon 64 X2 4600+?

    - by Software Monkey
    I recently rebuilt my 5 year old computer. I upgraded all core components, in particular from an Athlon 64 X2 4600+ at 2.4 GHz with DDR2 800 to a Phenom II 965 BE (quad core) at 3.6 GHz with DDR3 1333 (actually 1600, but testing consistently detected memory errors at 1600). The motherboard is also much newer and better. The HDD's (x3), DVD writer and card reader are the same. The BIOS memory config is auto-everything except the base timing which I overrode to 1T instead of 2T. The BIOS CPU multiplier is slightly over-clocked to 3.6 GHz from the stock 3.4 GHz. I noticed compiling Java is slower than I expected. As it happens I have some (single-threaded) Java pattern-matching code which is CPU and memory bound and for which I have performance numbers recorded on a number of hardware platforms, including my old system. So I did a test run on the new equipment and was stunned to find that the numbers are only slightly better than my old system, about 25%. The data set it is operating on is a 148,975 character array, which should easily fit in caches, but in any event the new CPU has larger caches all around. The system was, of course, otherwise idle for the test and the test run is a timed 10 seconds to eliminate scheduling anomalies. A long while ago, when I upgraded only memory from DD2 667 to DDR2 800 there was no change in performance of this test, which subjectively supports that the test cycle does not need to (significantly) access main memory, but yes it is creating and garbage collecting a large number of objects in the process of this test (low millions of matches are found for the pattern set). I am about 99.999% certain the code hasn't changed since I last ran it on 2009-03-17 - but I can't easily retest the old hardware, because it is currently in pieces on my work-bench waiting to be built into a new computer for my kids. Note that Windows (XP) reports a CPU speed of 795 MHz unless I have some thing running. With stuff running it seems to jump all over the place each time I use ALT-Pause to display the system properties, everywhere from 795 MHz to 3.4 Ghz. So why might my shiny new hardware under-performing so badly? EDIT: The old memory was Mushkin DDR2 800 with timings set for auto which should have been 5-5-5-12. The new memory is Corsair DDR3 1600, running at 1333 with timings also auto which are 9-9-9-21. In both cases they are a paired set of dual channel DIMMs. I was waiting to ensure my system was stable before tweaking with memory timings.

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  • No architecture vs architecture-specific binaries

    - by Aaron
    From what I understand, the noarch suffix means that it's architecture independent and should work universally. If this is the case, why should I install architecture-specific packages at all? Why not just go straight for the noarch? Are there optimizations in the x86 or x64 binaries that aren't found in the noarch binaries? What's best for high performance applications? Folding@Home does this with their controller:

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  • Any simple tools for re-loading a specified web page periodically (Windows)?

    - by Luke
    I've got a website that is exhibiting slow performance on the first load and would like to attempt to load it every 5 minutes or so to keep the cache fresh. Are there any simple tools to accomplish this? Scheduled tasks doesn't have quite the time resolution I need. The tricky thing is that this site uses Windows authentication so a wget script won't work. I'm also worried about instantiating a bunch of copies of internet explorer or attempting to kill iexplore.exe tasks blindly.

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  • What is good usage scenario for Rackspace Cloud Files CDN (powered by AKAMAI) [closed]

    - by Andrew Smith
    I have just setup my website as static page via Rackspace CDN / Akamai. www.example.co.uk is an alias for d9771e6f24423091aebc-345678991111238fabcdef6114258d0e1.r61.cf3.rackcdn.com. d9771e6f24423091aebc-345678991111238fabcdef6114258d0e1.r61.cf3.rackcdn.com is an alias for a61.rackcdn.com. a61.rackcdn.com is an alias for a61.rackcdn.com.mdc.edgesuite.net. a61.rackcdn.com.mdc.edgesuite.net is an alias for a63.dscg10.akamai.net. a63.dscg10.akamai.net has address 63.166.98.41 a63.dscg10.akamai.net has address 63.166.98.40 a63.dscg10.akamai.net has IPv6 address 2001:428:4c02::cda8:ecb9 a63.dscg10.akamai.net has IPv6 address 2001:428:4c02::cda8:ed09 The HTTP header: HTTP/1.0 200 OK Last-Modified: Fri, 19 Oct 2012 23:27:41 GMT ETag: fdf9e14b77def799e09e8ce815a521da X-Timestamp: 1350689261.23382 Content-Type: text/html X-Trans-Id: tx457979be3bd746c2b4e5403a1189cdbc Cache-Control: public, max-age=900 Expires: Sat, 27 Oct 2012 22:18:56 GMT Date: Sat, 27 Oct 2012 22:03:56 GMT Content-Length: 7124 Connection: keep-alive I am wondering, if it's really the fastest solution to power the website? By investigating it thru http://www.just-ping.com/ it seems, that from many places the ping is very high, and during quick investigation I found that they use GeoIP to resolve addresses based on WHOIS, which is not accurate and because of that from many places the ping is above 300ms (for example, if ISP is in balgladore and request is routed to bangladore even if it's 300ms, for period of 1 month), while by just using Amazon Web Services and Route 53 Anycast DNS servers and only 4 EC2 instances it seems that for example India is always below 100ms, while using Akamai it goes above 300ms in some cases, and this is because Route 53 is using BGP. By quickly checking the Akamai, it seems that they are not getting feedback from the traffic - the high ping stays constant even if I keep downloading large files and videos, which is opposite to what they say on their website. They state, that they optimize the performance by taking feedback from the requests, while it seems they just use GeoIP with per City resolution (which are mostly big cities). Because of this, AWS with Route 53 / Anycast DNS seems to be much more reliable, as well EdgeCast which is using BGP, but I dont know how much does it cost to deploy static website. Actually, I dont know if EdgeCast is not a lie, because from isolated places there are many errors - so their performance is at the cost of quality of delivery, because of BGP switching the routes during transfer of large files. So I was wondering, what is really Akamai good for, because they dont seem to pose any strength in any field in what I do understand now, except they offer some software based WAF on their website, but what I really care about is the core distribiution, so the question is? Is really Akamai good for Videos? For static websites? ??? I found so far AWS most usable with most consistent ping and stable transfers.

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  • How to clear Windows disk read cache?

    - by Sebastiaan Megens
    For performance testing I need to clear Windows' disk read cache. I tried googling but I couldn't find anything other than rebooting or other manual stuff. Before I give in and do that, I'd like to know if anyone knows of a way to clear Windows disk read cache. I'm testing on Windows 7, but I'm also interested in Windows XP solutions.

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  • Can anybody recommend a Windows system monitoring tool similar to iPulse for the Mac?

    - by John MacIntyre
    Occasionally, my PC grinds to a halt, and by the time I get any monitoring tools open (don't forget my PC is slow at this point), performance has picked up a bit. A friend recently told me he uses iPulse, which is awesome since it's always running, and you can just glance at it when there's an issue to see what is happening. Unfortunately it's only for the Mac. Does anybody know of a good Windows system monitoring tool similar to iPulse for the Mac?

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  • Can I enable discards on a LUKS-encrypted ssd drive in RHEL6 (and do I need to)?

    - by Dan Nestor
    I have a RHEL 6.4 workstation, running on a LUKS-encrypted LV residing on a SSD. I found RedHat documentation stating that dm_crypt does not currently support TRIM passthrough, however I also found other sources that state the opposite (albeit for other distributions) and even that discards are not needed for recent SSD drives which use some sort of automatic garbage collection. So: 1) Can I enable TRIM/discards with my setup? 2) Do I need to, for optimal disk performance? Thanks for your thoughts.

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  • Are there any reasons to duplicate table in the same database ?

    - by bob
    Let says we have several MySQL server, one master and some slaves. A member table which contains more than 5.000.000 peoples. Are there any reasons (performance, atomicity, etc..) to use duplicate tables like member_1, member_2, member_3 and then switch randomly when doing operation on it ? (especialy SELECT query) ?

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  • Linux server became extremely slow

    - by Ariel Aharonson
    I have a file sharing website, and my files hosted in a server with those system specifications: 32GB RAM 12x3TB 2x Intel Quad Core E5620 I have files in this server up to 4gb for each file. 446gb is full (/36TB) [root@hosted-by ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 50G 2.7G 44G 6% / tmpfs 16G 0 16G 0% /dev/shm /dev/sda1 97M 57M 36M 62% /boot /dev/mapper/VolGroup01-LogVol00 33T 494G 33T 2% /home And take a look at this: Why is the wa% so high? (I think that what makes the server to be so slow)

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  • Faster zlib alternatives

    - by BarsMonster
    I wonder, if there are any faster builds of zlib around with more advanced optimizations? If it's possible to optimize it using SSE instructions or Intel C++ compiller, or some trick which were patented earlier (I know patents were a serious limitation during gzip/zlib development), have anyone bothered to implement that? I am especially interested in compression speed, which have a direct impact on high-performance web-services serving static & dynamic content.

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  • Is CloudLinux considered to be a stable webserver

    - by Saif Bechan
    I am currently running several websites on a CentOS 5.4 system. I have the choice to switch to Cloudlinux. It is said to be better at handling several websites. Does anyone have any information to share on CloudLinux. This can be on security, stability and just overall performance of the system.

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  • Echo 404 directly from nginx to improve performance

    - by user64204
    I am in charge of production servers serving static content for a website. Those servers are constantly being crawled by bots looking for potential exploits (which isn't that much of a problem security-wise because no application can be reached behind the web server) but generates thousands of 404 per day, sometimes per hour. I am looking into ways of blocking those requests but it's tricky (you want to make sure you don't block legitimate traffic and these bots are becoming more and more clever at looking like they're legit) and is going to take me a while to find an acceptable solution. In the meantime I would like to reduce the performance impact of serving those 404 pages. Indeed we're using nginx which by default is configured to serve it's 404 page from the disk (This can be changed using the error_page directive but in the end the 404 will either have to be served from disk or from another external source (e.g. upstream application which would be worst)) which isn't ideal. I ran a test with ab on my local machine with a basic configuration: in one case I echo a message directly from nginx so the disk isn't touched at all, in the other case I hit a missing page and nginx serves its 404 from disk. server { # [...] the default nginx stuff location / { } location /this_page_exists { echo "this page was found"; } } Here are the test results (my laptop has Intel(R) Core(TM) i7-2670QM + SSD in case you're wondering why they are so high): $ ab -n 500000 -c 1000 http://localhost/this_page_exists Requests per second: 25609.16 [#/sec] (mean) $ ab -n 500000 -c 1000 http://localhost/this_page_doesnt_exists Requests per second: 22905.72 [#/sec] (mean) As you can see, returning a value with echo is 11% ((25609-22905)÷22905×100) faster than serving the 404 page from disk. Accordingly I would like to echo a simple 404 Page not Found string from nginx. I tried many things so far but they all failed, essentially the idea was this: location / { try_files $uri @not_found; } location @not_found { echo "404 - Page not found"; } The problem is that as soon as the echo directive is used, the http response code is set to 200. I tried changing that by doing error_page 200 = 400 but that breaks the configuration. How can I serve a 404 page directly from nginx? (without hacking the source which may be might next step)

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  • Why does Kerberos need Ticket Granting Server?

    - by Narsil
    It's probably something fundamental but I can't find a certain statement. Why can't KDC authenticate then provide the service ticket directly. Is it about security or performance or some other thing? Since users don't log in each time they request a service and assumably they will keep logged in for a long time, AS doesn't seem so busy. Why do they have to be seperated?

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  • iotop for Linux kernel 2.6.18

    - by Lightsauce
    So it has to come to my attention that iotop isn't availalbe for 2.6.18 since it's less than 2.6.20 and requires Python 2.6+. I've done some research and came across this article: http://lserinol.blogspot.com/2009/09/io-usage-per-process-on-linux.html According to this, if these process have io stats in /proc/pid#/io (where pid# is the process #) it's doable regardless of the kernel version. So, in reality, I could upgrade Python to 2.6 and test out iotop. However, my flavor of Linux, CentOS release 5.5 (Final), only supports Python 2.4.3-44.el5 currently. If I were to do uninstall from yum, it doesn't look so pretty. It ends up wanting to uninstall 235 packages, most of which are very important! I read in one place, online (I forget the URL from yesterday), that you can install Python 2.6+ parallel to this one, and have the rpm install for iotop use that. Well, I didn't choose that route. I figured, what the heck, lets write iotop (not copying it, but reverse engineering it without actually looking at it's code/it in use) in bash. I thought it would just grab the /proc/pid#/io file and parse stats. So I wrote a script to grab the top 10 rchar, wchar, read_bytes, and write_bytes by collecting all these stats from all the /proc/pid#/io files, sorting them by each metric, then grabbing the top 10 highest values. The conclusion, the data seems completely useless. Does anybody know any resources for advanced Linux where I can figure out how to take these /proc/pid#/ directories and figure out what the heck they are doing with io on the disk? My main goal is to figure out what exactly is causing high load on my disk. I just know it's on the / partition (/dev/sda2 in this case), and I'm not really sure how to narrow it down without the help of iotop. If I run iostat to grab metrics for 1 minute, every second, the first result it gives me shows a high 'kB_read/s', so that makes me think, it's reading mostly. However, if I watch the update it gives me every second, it's actually just showing values for kB_wrtn/s. This makes me think the initial value iostat gives me is misleading.

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