[Dovecot] performance problems with IMAPS

[Timo Sirainen]

On 10.5.2011, at 22.45, Linda Walsh wrote:

> I've noticed this before and wasn't sure of the problem -- sending large files from FF.

What is FF?

> I tracked it down, and the problem is in dovecot when it is saving the mail to my 'Record' (Outbox)...

So when IMAP client is sending a message to Dovecot?

> It's saving the file in tiny chunks....
> 
> Looking at a few, I see:
> 4148 bytes
> 2116 bytes
> 1604 bytes
> 692 bytes

Isn't that the client that is sending it in small pieces then? How did you measure those bytes?

> The latency is killing it.  I see the TCP window size being as high as 17069 with 7678 being common.
> The sendmail latency isn't spectacular, but at least uses ~64K packets.  So wazzup with dovecot?

Whatever it is, it's not a common problem.