[Dovecot] Performance-Tuning

[Stan Hoeppner]

On 11/14/2011 4:27 AM, Jan-Frode Myklebust wrote:

> Agree. A non-clustered fs should give you better performance, and
> probably also be more reliable, if you can live with the SPoF and
> full downtime during patching/upgrades/maintenance. But I would expect
> xfs to be a better choice than ext*.

Depends on the workload characteristics and how well the XFS filesystem
is tuned to the storage hardware.  If setup properly, using many
allocation groups with fast spindles, a decent amount of BBWC, and a
high concurrency maildir workload (dozens to hundreds of delivery and
IMAP operations), XFS will runs circles around EXTx as it can
create/write/read to every AG in parallel.  Much of EXT4's operation is
still serialized.  This is why XFS outruns all other filesystems in the
highly parallel mail workload benchmarks I posted previously, EXTx by a
factor of 2-3.

For smaller hosts that don't see parallelism, for example SOHO servers,
XFS will likely be slower than EXTx as the workload will be serialized.

-- 
Stan