Re: High iowait

Lothar,

Thanks for the reply.

Basically i am not able to achieve the kind of throughput which i
should get from my RAID system. And i think the OS is the culprit
(some bug in the vendor kernel) since for some reason it goes into
huge iowaits preventing the applications to read/write more data. How
can i debug whether the problem is with the OS or with the device?

TIA

On 8/22/06, Lothar Braun <[email protected]> wrote:
> Hi,
>
> On Tuesday 22 August 2006 04:31, [email protected] wrote:
> > I have a storage raid attached to my linux server running CentOS 4.3
> > kernel 2.6.9-39.0.2.ELsmp. My server goes into huge iowait when i try
> > to read/write lot of data to the storage device. How can i debug
> > whether the problem is with the storage device or some setting of the
> > operating system. Is there any known issue with this kernel? How can i
> > tune my system to reduce iowait time?
>
> Why should you want to reduce the iowait time? Iowait, as shown by top,
> means
> afaik that there are some processes waiting for io to complete  and nothing
> else to do for the processor.
> If you're running some CPU eating processes while your I/O operations are
> performed, then the iowait value should go down (this is because your CPU
> can
> then do more sophisticated work than waiting)
>
> Regards,
> Lothar
>
>