[Dovecot] Proxying Performance vs imapproxy

[Ed W]

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