Jose Celestino wrote:
On Seg, 2009-09-28 at 15:55 +0100, Ed W wrote:
You didn't get much answer to this - I'm probably not the best person to
answer, but
Are there any performance benefits to using a proxying server, or is it just
for splitting mailstores?
I think this is the main reason for the proxying option. It would
appear that others have measured the performance load of the proxy task
and found it near negligible? Hence it seems possible to use a bunch of
backend servers and a few frontend servers to forward the user to the
correct backend server. I believe each connection needs to be setup
each time though, so for sure some more advanced proxies with persistent
caching of connections may offer a performance improvement if your
servers are loaded due to the login part (but I guess measure this first
before assuming it's so?)
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
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.
Caveat: I don't have anything like this kind of setup and am not
offering an informed opinion...
Good luck
Ed W
