I have some problems with my system performance. As I was adviced here, I used
$sar -u 5
and found out that the problems are caused by a low HDD performance, as I supposed (high
My disk is Western Digital AV-25, WDC WD5000BUDT-63G8FY0. Vendor specification can be found here.
# <file system> <dir> <type> <options> <dump> <pass> devpts /dev/pts devpts defaults 0 0 shm /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 0
The 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?
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