[Dovecot] dovecot evaluation on a 30 gb mailbox

[Noel Butler]

On Fri, 2010-06-25 at 02:18 +0100, Timo Sirainen wrote:

> On 25.6.2010, at 1.37, Noel Butler wrote:
> 
> > If its running on a SOHO, you probably wouldn't even be able to measure
> > the difference, but for an ISP/Telco or large institution, you will
> > certainly notice the reduction in I/O (or loads on your database
> > server). This goes for any imap webmail software, not just SM.
> 
> But with auth cache enabled, there is no extra database load. The index files are also most likely in OS's cache (assuming local disk), so no extra disk I/O to read them either. I'm sure it's a bit more extra CPU usage, but I'm not all that certain that it's really that a big of a difference with Dovecot.
> 


auth_cache_size = 512
auth_cache_ttl = 3600
auth_cache_negative_ttl = 0

So, we use it at 512KB, perhaps this value was just too small, but
admittedly, this change was made back in the early 0.9 days, and since
imapproxy cured the problems, we (ok.. I :->) decided it shall be
mandatory with all webmail servers since...  I'll drop it off on one of
them for a day or so and keep an eye on it.