Re: High load and iowait but no disk access

On 30-Aug-05, at 12:15, Tom Lane wrote:

> =?ISO-8859-1?Q?R=E9my_Beaumont?= <remyb(at)medrium(dot)com> writes:
>> The stats of the NetApp do confirm that it is sitting idle.
>
> Really?

>
>> CPU NFS CIFS HTTP Total Net kB/s Disk kB/s Tape kB/s
>> Cache Cache CP CP Disk DAFS FCP iSCSI FCP kB/s
>> in out read write read write
>> age hit time ty util in out
>> 2% 0 0 0 139 0 0 2788 0 0 0
>> 3 96% 0% - 15% 0 139 0 3 2277
>> 2% 0 0 0 144 0 0 2504 0 0 0
>> 3 96% 0% - 18% 0 144 0 3 2150
>> 2% 0 0 0 130 0 0 2212 0 0 0
>> 3 96% 0% - 13% 0 130 0 3 1879
>> 3% 0 0 0 169 0 0 2937 80 0 0
>> 3 96% 0% - 13% 0 169 0 4 2718
>> 2% 0 0 0 139 0 0 2448 0 0 0
>> 3 96% 0% - 12% 0 139 0 3 2096
>
> I know zip about NetApps, but doesn't the 8th column indicate pretty
> steady disk reads?
Yes, but they are very low.
At 15% usage, it's pretty much sitting idle if you consider that the OS
reports that one of the processor is spending more then 80% of it's
time in IOwait.

Rémy
>
> regards, tom lane