[Gllug] Identifying what processes are waiting on IO

[Kostas Georgiou]

On Sun, Dec 07, 2008 at 02:18:05PM +0000, John Hearns wrote:

> Once you've identified the processes and disk devices which are
> causing the problems, then maybe a bit of lateral thought can help. As
> a for instance, one of the applications I'm familiar with, Ganglia,
> uses a round-robin-tool database, which is frequently updated with
> information from Beowulf cluster nodes - so frequently that on a big
> cluster the didks are just continually busy. The recognised fix is to
> write the data to a RAMdisk then flush to real disk every so often.

I just mount /var/lib/ganglia with noatime,data=writeback,commit=180
which has a similar effect.

Kostas
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