[Dovecot] auth_cache_size

[Timo Sirainen]

On Fri, 2010-06-25 at 08:09 -0700, Daniel L. Miller wrote:
> Let's start small.  Assume ten users, all connected - and everybody also 
> likes looking at everybody else's mailbox.  So there are ten clients, 
> each with at least ten connections (I say at least because each folder 
> viewed within an account is its own connection, right?).
> 
> How is the auth_cache used?  If I have ten user/pass combinations - is 
> that all that is stored?

It caches passdb and userdb lookups+replies. Both are independent of
each others.

> Or are there connection-specific entries as well?

No.

> In other words, for the above example, do I have 10 x 250 bytes 
> yields auth_cache_size=3, or do I need 10 x 10 x 250 yields 
> auth_cache_size=30 - or am I totally off?

10 x 250. But negative hits ("user not found") are also cached (unless
you disable them) and they can also increase the cache usage.