[Mimedefang] MD I/O intensive?

[Stephen Smoogen]

On Tue, 2004-03-16 at 07:56, Andrew J Caird wrote:
> Quoting WBrown at e1b.org:
> 
> > mimedefang-bounces at lists.roaringpenguin.com wrote on 03/15/2004 06:11:14 
> > PM:
> > 
> > > I read somewhere that reiserfs is faster then ext3 on small file
> > > deletion/creation. Typical mail load.
> > > On a high load site, would type of file system really matter?
> > 
> > The testing in "sendmail Performance Tuning" indicates that ext3 is 
> > faster. Even ext2 is faster than Reiser.  See section 3.3.3, pgs. 42-43.
> 
>   I can't say enough about this book, it's very dense, but worth reading
>   a couple of times.  Anyone running high-performance email systems would
>   be well served by reading it.
> 
>   The other thing to keep in mind is that there is more to filesystems
>   than speed when it comes to email - they also have to be reliable and
>   be able to insure message storage.  Of course, for MD's temp space the
>   opposite is true - message persistance (beyond a few seconds) isn't
>   important and speed is all that matters.  See Christenson's book for
>   a more educated discussion of these issues.

Exactly.. the problem that people forget  is that even with a 15k disk
there is a lot more time involved than sending data to a RAM disk. [My
little test with bonnie++ on linux a long time ago showed it was at
least 10x faster than any disk drive+filesystem.. the bottleneck being
the CPU/MMU]. 

If you can afford it getting a hardware RAMdisk that backs up to
diskdrive is also good for /var/spool.  The speeds were limited to what
the SCSI pipe could send it. [Sigh I had to return mine :(].

-- 
Stephen John Smoogen		smoogen at lanl.gov
Los Alamos National Lab  CCN-5 Sched 5/40  PH: 4-0645
Ta-03 SM-1498 MailStop B255 DP 10S  Los Alamos, NM 87545
-- So shines a good deed in a weary world. = Willy Wonka --