Re: mail queue's, ext3 data=journal and sync-mount
I decided that this message is better for Debian-ISP, so I replied to the
list and BCC'd you. I hope you don't object.
On Sun, 18 Aug 2002 01:20, you wrote:
> I'm having some trouble finding info on this stuff and found a
> knowledgeable-sounding post of yours on debian-isp. Please ignore if
> this is inappropriate.
> I'm going to setup a debian woody system for qmail (and others) and was
> hoping to secure the qmail queue a bit. For some reason, sync mounted
> ext2 and 3 is abysmally slow. How does FFS do it? anyway, do you know
> if ext3 mounted data=journal (or any other way) is sufficient?
I have not done any serious tests on such things. If you want to do such
tests then I recommend my Postal benchmark program (it's in Debian). But
don't try the IMAP option - I haven't finished coding it.
Rumour has it that data=journal can actually improve performance in some
situations. If a program is writing lots of small files synchronously (quite
common for a mail server that has one tiny control file for every message,
and the average message file isn't too big) then journalling the data allows
for synchronous writes to a small (8M to 32M) region on disk (which is really
fast) and it'll then be written to it's final destination with the write-back
caching enabled which allows writes to be ordered for good performance.
I haven't tested this but it all sounds logical.
Without the data=journal option ReiserFS is rumoured to beat Ext3, with
data=journal ext3 should win.
I don't know much about FFS.
I would be interested in seeing benchmark data. Also one thing I have been
thinking of doing is benchmarking Qmail vs Postfix... ;)