[Dovecot] Performance of Maildir vs sdbox/mdbox

[Jan-Frode Myklebust]

On Mon, Feb 06, 2012 at 10:29:03PM +0200, Timo Sirainen wrote:
> On 3.2.2012, at 14.25, Jan-Frode Myklebust wrote:
> 
> > I now implemented this patch on our directors, and pointed postfix at them.
> > No problem seen so far, but I'm still a bit uncertain about the
> > LMTP_PROXY_DATA_INPUT_TIMEOUT_MSECS. I know we're experienceing quite
> > large delays when fsync'ing (slow IMAP APPEND). Do you think increasing
> > LMTP_PROXY_DATA_INPUT_TIMEOUT_MSECS is a sensible workaround if we start
> > seeing lmtp_proxy_output_timeout problems again ?
> 
> Your fsyncs can run over 60 seconds?

Hopefully not.. maybe just me being confused by the error message about
"lmtp_proxy_output_timeout". After adding
http://hg.dovecot.org/dovecot-2.0/rev/71084b799a6c on friday, we haven't
seen any problems so it looks like this problem is solved.

But it doesn't seem unthinkable that ext3 users might see more than 60s
for fsyncs... "Some stalls on the order of minutes have been reported"
ref: https://lwn.net/Articles/328363/

> I think even if you increase Dovecot's timeout you'll soon reach your MTA's LMTP timeout.
> 

My MTA's default is 10 minutes..

	http://www.postfix.org/postconf.5.html#lmtp_data_done_timeout



  -jf