On Mon, Oct 5, 2009 at 5:17 AM, Michal Vitecek <fuf@mageo.cz> wrote:
> Could the problem be the HW RAID card? There's ServerRAID 8k with 256MB
> with write-back enabled. Could it be that its internal cache becomes
> full and all disk I/O operations are delayed until it writes all
> changes to hard drives?
that's possible...the red flag is going to be iowait. if your server
can't keep up with the sync demands for example, you will eventually
outrun the write cache and you can start to see slow queries. With
your server though it would take in the hundreds of (write)
transactions per second to do that minimum.
merlin