Re: Performance problems with 3ware 9500S-4LP and 2.6.25-rc3

Andre Noll
2008-02-27T10:14:30Z

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On 13:33, Chris Snook wrote:

> >During the daily cron job that uses rsync to sync a 500G file system
> >from another machine to the raid on the 3ware controller the load
> >jumps up, and the machine becomes sluggish as hell. For example, an
> >ssh login to that machine takes minutes to complete and ldap becomes
> >unreliable while the rsync job is running. Even Nagios complains
> >about the machine being down while rsync is running.
>
> You're putting your box under astronomical load. This is generally
> regarded as a bad idea, regardless of how well your storage controller
> is performing.

The machine becomes sluggish also when I write directly to the raid
array. A simple

dd if=/dev/zero of=tmpfile

shouldn't push the load up to 4, right?

> Can you measure the single-threaded throughput (say,
> coping one huge file, and then syncing) to give us a baseline
> performance figure?

Single threaded throughput seems to be ok (140M/s). The problem is
that the machine becomes unresponsive.