[CentOS] Find reason for heavy load
Noob Centos Admin
centos.admin at gmail.com
Thu Dec 31 09:26:12 UTC 2009
Hi,
> Dstat could at least tell you if your problem is CPU or I/O.
This was the result of running the following command which I obtained
from reading up about two weeks ago when I started trying to
investigate the abnormal server behaviour.
dstat -c --top-cpu -d --top-bio --top-latency
usr sys idl wai hiq siq| cpu process | read writ| latency process
4 1 93 2 0 0|mysqld 0.0| 80k 82k|khelper 8
42 46 0 12 0 0|httpd 12| 648k 0 |ksoftirqd/0 111
26 37 12 26 0 0|httpd 1.5| 520k 11M|ksoftirqd/1 75
23 49 8 19 0 0|exim 1.0| 652k 16k|ksoftirqd/0 44
26 44 3 28 0 0|exim 1.0| 652k 1296k|ksoftirqd/0 44
32 41 4 23 0 0|exim 1.5| 620k 16k|ksoftirqd/0 50
28 52 3 16 0 0|exim 1.5| 700k 0 |ksoftirqd/1 47
21 41 11 28 0 0|exim 1.0| 556k 11M|ksoftirqd/0 79
27 46 3 24 0 0|exim 1.5| 684k 16k|ksoftirqd/1 40
29 45 2 24 0 0|exim 1.0| 672k 944k|ksoftirqd/0 25
28 33 3 37 0 0|httpd 14| 852k 5992k|ksoftirqd/1 39
36 39 2 23 0 0|httpd 5.0|1024k 0 |ksoftirqd/0 84
> Even better, run
>
> vmstat 2 10
>
> Look at the first two columns. What column have higher numbers? If r,
> you're CPU-bound. If b, you're I/O bound.
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
r b swpd free buff cache si so bi bo in cs us sy id wa st
8 1 3092 131460 100692 833668 0 0 40 21 1 0 4 1 92 2 0
9 1 3092 130708 100700 835016 0 0 578 206 577 1420 32 50 3 15 0
7 1 3092 128324 100716 836148 0 0 546 2866 594 1465 31 44 7 18 0
4 1 3092 126860 100724 837268 0 0 540 256 596 1505 28 43 6 23 0
7 2 3092 125600 100740 838564 0 0 620 234 661 1442 30 41 2 26 0
5 1 3092 124028 100756 839752 0 0 570 2692 635 1430 24 45 6 25 0
6 0 3092 122040 100784 840964 0 0 584 1464 682 1434 27 44 2 28 0
6 1 3092 120588 100792 842232 0 0 602 278 624 1562 32 46 2 20 0
2 3 3092 120556 100840 843064 0 0 440 2908 603 1299 22 35 6 37 0
3 1 3092 119832 100876 844088 0 0 430 1104 605 1348 23 36 1 40 0
According to this, am I correct to conclude that I'm CPU bound and the
system is busy doing some unknown processing?
> Did you check if you have a defect disk or a rebuilding array? That
> could be the cause.
I usually run a "cat /proc/mdstat" whenever I log into the server to
check my MD raid status. So far the array appears ok. There are no
disk warning when I run "dmesg". smartctl also reports no error logged
and passed for both disks, although no self test was ran. Would I be
safe to conclude that the disks are OK and not part of the problem?
Thanks again to everybody for the suggestions and help so far.
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