Performance problem

[Kenneth Marshall]

On Fri, Aug 05, 2016 at 11:11:33AM -0400, Eric W. Bates via Info-cyrus wrote:
> We are migrating our cyrus from a venerable computer to a new one.
> 
> We've been gradually moving individuals over to the new machine and are
> quite surprised at the poor performance characteristics we're seeing on
> the new machine.
> 
> The new machine:
>  2 @ 6 core Xeon E5-2640
>  256 Gb memory
>  zfs built on 18 SAS drives with SSDs for zfs cache and log
>  Freebsd 10.2-RELEASE-p7
>  Cyrus imapd 2.5.7
> 
> There are approximately 1000 copies of imapd running at any given moment.
> 
> The load average hovers around 5.
> 
> Can anyone suggest what we might look at to assess why imapd seems to be
> such heavy lifting?
> 
> -- 
> Clark 159a, MS 46
> 508/289-3112
> 

Hi Eric,

How many users do you have? It is typical to have one or more imapd
processes per user. Look at the I/O stats for your filesystems to
see if you have a bottleneck somewhere. Also, what type of SSDs are
you using for your ZFS log devices? We found we needed RAM-style
SSDs to maximize our I/O performance under ZFS.

Regards,
Ken