Re: Who is causing the iowait?

From: tunla (lars.tunkrans_at_bredband.net)
Date: 06/28/05 

Date: 28 Jun 2005 12:05:54 -0700

VA wrote:
> Solaris 8. I see the following in top
>
> Who is causing the 56.8% iowait? How can I tell which processes are
> contributing to this iowait?
>

   well in your case the most likely culprit is the the Kernel.
this is because your machine is starved for memory You are having
1.2 GB data on swap and only 1 GB RAM. so most likely you system disk
is thrashed. Check how many I/O ops the system disk is doing.
95% of these are probably to the swap area. A singel 10.000 rpm disk
does approx 150 I/O ops per second.

You probably need to buy another Gigabyte of RAM.

Oracle needs a lot of RAM.
What is the size of the ORACLE SGA ?

//Lars

> load averages: 0.20, 0.20, 0.40
> xxxxx 14:39:14
> 168 processes: 165 sleeping, 2 stopped, 1 on cpu
> CPU states: 34.1% idle, 1.1% user, 8.0% kernel, 56.8% iowait, 0.0%
> swap
> Memory: 1024M real, 15.1M free, 1.2G swap in use, 1.9G swap free
>
> PID USERNAME THR PR NCE SIZE RES STATE TIME FLTS CPU COMMAND
> 11343 oracle 1 58 0 6368K 2448K sleep 0:04 0 4.92% xterm
> 16583 root 1 40 0 10.7M 3960K sleep 410:31 0 3.72% smbd
> 2278 root 5 60 0 130M 85.7M sleep 59.0H 539 0.82%
> vts_msgmon
> 11448 oracle 1 48 0 2624K 1640K cpu00 0:00 0 0.47% top
> 11049 oracle 1 58 0 380M 337M sleep 0:06 0 0.11% oracle
> 608 root 1 58 0 2848K 1464K sleep 88:01 0 0.09% nmbd
> 1946 root 16 58 0 39.3M 5576K sleep 76:12 88 0.08% java
> 9763 oracle 25 58 0 387M 330M sleep 117:02 0 0.06% oracle
> 11053 oracle 1 58 0 379M 337M sleep 0:06 0 0.06% oracle
> 5696 root 1 58 0 1984K 904K sleep 223:15 0 0.05%
> sma_disp
> 25670 root 1 58 0 4936K 2632K sleep 0:30 36 0.04% smbd
> 11440 oracle 1 58 0 380M 337M sleep 0:00 0 0.04% oracle
> 9761 oracle 16 58 0 389M 330M sleep 75:31 0 0.03% oracle
> 28233 oracle 11 58 0 383M 338M sleep 1:48 0 0.02% oracle
> 28136 oracle 11 58 0 383M 338M sleep 1:40 0 0.02% oracle
>
> Thanks for any help

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