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Re: [Dovecot] IMAP-proxy or not with sogo webmail and dovecot backend Ed W Wed Feb 22 02:00:38 2012

On 22/02/2012 08:25, Jan-Frode Myklebust wrote:
On Tue, Feb 21, 2012 at 02:33:24PM +0000, Ed W wrote:
I think the original question was still sensible.  In your case it
seems like the ping times are identical between:
     webmail ->  imap-proxy
     webmail ->  imap server

I think your results show that a proxy has little (or negative)
benefit in this situation, but it seems feasible that a proxy could
eliminate several RTT trips in the event that the proxy is "closer"
than the imap server?  This might happen if say the imap server is
in a different datacenter (webmail on an office server machine?)
The webmail/imapproxy were actually running in a different datacenter to
the dovecot director/backend servers, but only about 20KM away.

Ping tests:


        rtt min/avg/max/mdev = 0.933/1.061/2.034/0.183 ms


        rtt min/avg/max/mdev = 0.104/0.108/0.127/0.005 ms


        rtt min/avg/max/mdev = 0.020/0.062/1.866/0.257 ms


Hmm, not sure I understand the original numbers then?

It seems intuitive that the proxy installed locally could save you 2x RTT increment, which is about 0.8ms in your case. So I might expect the proxy to reduce rendering times by around 1.6ms simply because it reduces the number of round trips to login? Kind of curious why that's not achieved..?


Ed W