[Gllug] Identifying what processes are waiting on IO

[Byron Schlemmer]

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On 7 Dec 2008, at 11:09, Stephen Nelson-Smith wrote:

> I have a system whose load is very high for several hours .  It's a  
> quad
> core machine, and I'm seeing load of around 20.
>
> The system becomes somewhat unresponsive during this time - and
> customers are complaining.
>
> Investigating further, I see that the system sees a drop in the amount
> of memory used as buffers by the kernel, and I notice that all 4 cores
> spend a very large amount of time in iowait.
>
> Looking at the disk performance, I see device saturation - the
> percentage  of CPU time during which I/O requests were issued to the
> device is at 100%
>
> I would like to be able to find out what processes are using the  
> disks,
> and waiting on IO - so I can consider either moving them to other
> machines, or consider reconfiguring storage in a way that is better
> suited to the application profile.

Tried http://guichaz.free.fr/iotop ?
- --

	byron

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