Hi Stephen, Sam,
Thanks for the suggestions. I did increase innodb_buffer_pool_size
during Friday to 2GB and it seemed to have no effect. However at about
09:00 on Saturday the load quickly dropped to a very low value and has
been like that since (except for a couple of brief excursions to a load
of 1). Either some external operation which I've not seen before really
did start at the same time as the upgrade, or the upgrade caused a
strange knock-on activity which look 36 hours to complete. I haven't yet
had chance to see if I can find a correlation with external activities.
Thanks for all the helpful suggestions from various people - much
appreciated.
John
On 21/01/2013 11:37, Sam Skipsey wrote:
> Indeed, the DPM tuning advice (written mostly by Alessandra and I)
> recommends having a big buffer pool size for precisely that reason.
> Try setting it to at least 1GB, but up to 4GB if you need to.
>
> Sam
>
>
> On 21 January 2013 11:32, Stephen Jones <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
> On 01/18/2013 12:15 PM, John Hill wrote:
>
> About 14GB. 8GB memory was fine with DPM 1.8.3, so if it is
> inadequate
> now then something significant has changed - and there's nothing in
> the Release Notes highlighting the need for a larger machine for
> 1.8.4 or 1.8.5.
>
>
> Hi John,
>
> I don't know very much about mysql, but Oracle would struggle
> if the "buffer cache" was too small. It would have to keep paging
> blocks out to fit new ones in, which made it waity. Maybe check that
> you have decent buffers on your DB. I know there are some
> settings in the /etc/my.cfg e.g. maybe
> set-variable=innodb_buffer___pool_size=8000M,
> (or query_cache_size=16000000???)
>
> If you have 8GB of mem, some DBA's recommend using half of it
> for the buffer cache (assuming nothing else but the OS runs there).
>
> That's very naive, so I guess you'd have to select an appropriate size
> if other services run there. I dunno - just a few ideas...
>
> Steve
>
>
>
>
>
>
>
>
>
> --
> Steve Jones [log in to unmask] <mailto:[log in to unmask]>
> System Administrator office: 220
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>
>
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