I have some problems with my system performance. As I was adviced here, I used sar: $sar -u 5and found out that the problems are caused by a low HDD performance, as I supposed (high %iowait). My disk is Western Digital AV-25, WDC WD5000BUDT-63G8FY0. Vendor specification can be found here. /etc/fstab:# <file system>        <dir>         <type>    <options>          <dump> <pass>devpts                 /dev/pts      devpts    defaults            0      0shm                    /dev/shm      tmpfs     nodev,nosuid        0      0/dev/sda2 / ext4 defaults,noatime,data=writeback,barrier=0,nobh,errors=remount-ro 0 1/dev/sda3 /home ext4 defaults,noatime,data=writeback,barrier=0,nobh,errors=remount-ro 0 1/dev/sda4 swap swap defaults 0 0The problem is that from time to time some application (Minecraft game, Chromium browser, Eclipse) hangs up, my processor activity LED turns on, iowait goes to some 50% or more (I have dual core processor) and stays like this for a couple of seconds. Similar things happen when I use applications for the first time after reboot. The worst situation ever was forcing the system to use the swap partition (by some stress tool), the system went unusable.What can i do now to determine the exact cause of the performance problems? Is it the low hardware performance, some problems with linux io scheduler, application specific problems or something else?EDIT:Output of hdparm -t -T /dev/sda under no load:/dev/sda: Timing cached reads:   6244 MB in  2.00 seconds = 3129.13 MB/sec Timing buffered disk reads: 230 MB in  3.01 seconds =  76.33 MB/sec
GNU/Linux, IO performance problems
linux;performance;disk usage;io