Performance numbers for a DELL R710

[Steve Freegard]

Zaeem Arshad wrote:
> 
> 
> On Thu, Jun 4, 2009 at 6:38 PM, Steve Freegard <steve.freegard at fsl.com
> <mailto:steve.freegard at fsl.com>> wrote:
> 
>     Alex Neuman wrote:
>     > you mentioned asynchronous logging... Can you point us to a FAQ or a
>     > description of how this works, and why it's a good thing? Any cons?
> 
>     I believe this is already in the MAQ/Wiki.
> 
>     To enable asynchronous logging you change your syslog.conf entry from:
> 
>     mail.*                  /var/log/maillog
> 
>     to
> 
>     mail.*                  -/var/log/maillog
> 
>     On a mail server this can have a considerable effect on performance as
>     syslog doesn't run sync() calls after each write and therefore allows
>     the kernel to manage the writes to disk which can have a considerable
>     advantage for disk IO but with the disadvantage that if the machine
>     crashes or loses power that you'll be missing some of the most recent
>     log entries.  As part of any performance tuning - I *always* enable
>     this.
> 
> 
> Apart from this, I have found that moving to XFS or ext4 (if you have
> the courage) makes queue handling pretty fast. With the 24 GB RAM, I am
> considering having my hold queue on the tmpfs. This though carries the
> risk of mail loss in case of an power outage for which I have sufficient
> arrangements. Has anyone used other filesystems such as JFS or Reiser or
> even ext2? What's your experience?
> 

Twiddling with the filesystem used is only going to bring marginal gains
on your actual scan times which if you want to achieve 65 message/sec is
where you need to focus your efforts first.

I've seen XFS consistently come last in several benchmarks for mail
server type traffic. See http://www.linux-mag.com/id/7345/2/ for a
review of filesystems I read yesterday.

Regards,
Steve.