[Dovecot] Proxying Performance vs imapproxy

[Jose Celestino]

On Seg, 2009-09-28 at 14:06 -0400, Timo Sirainen wrote:
> On Mon, 2009-09-28 at 19:02 +0100, Ed W wrote:
> > > Proxy servers are usually set between the webmail and the imap server.
> > >
> > > That's because webmails are a bitch regarding opening+closing
> > > connections and so the proxy gets most of connection + auth + do
> > > something + disconnect and keeps a limited pool of per user connections
> > > to the imap servers that it re-uses. Proxies are usually installed on
> > > the same servers that the webmail, with the webmail connecting to
> > > 127.0.0.1:someport.
> > >
> > >   
> > 
> > That's what he was asking about, however, I don't think that dovecot's 
> > proxy does in fact do this for you?  I believe
> 
> Right, Dovecot doesn't do connection caching.
> 
> > However, it's probably worth checking if it's an issue in your 
> > installation before over tuning - I think that dovecot's login caching 
> > can make this a fairly inexpensive process.
> 
> Yeah. imapproxy probably reduces the load a bit, but it probably isn't
> anything dramatic with Dovecot. My guess is that it would only reduce
> CPU load, but if it's at ~1% already then there's not that much point..

No, you're right, it was much much worse with courier-imap :) We haven't
really measured it since it was so obvious with courier. But we do spare
some time with fs stats and checkpassword work, and we get a ready
connection with a hot cache.


-- Jose Celestino SAPO.pt::Systems http://www.sapo.pt
--------------------------------------------------------------------- *
Progress (n.): The process through which Usenet has evolved from smart
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