Gluster users - Oct 2012 - Gluster and maildir

Hello,

I am working on an email solution using Gluster 3.3 for the primary
storage of the actual email.? The system is using dovecot and
maildir.? I will be using 10 servers for this configuration (hardware
servers, not virtual systems) and I have a question about the setting
this up with performance in mind.? I've used gluster in the past and
had varying success.? For this problem, I have two specific options
and I'm looking for advice on which one would perform better.

1) 10 servers? --? 4 systems would be 2U systems with ALL of the
storage for email on them.? These 4 systems would also be running
services pertaining to email systems (IMAP/POP, SMTP, etc...).? The
remaining 6 systems are 1U systems and would connect to these systems
for email storage while running email services (IMAP/POP, SMTP,
etc...).

2) 10 servers? --? 10 1U servers running both storage and all
services? (IMAP/POP, SMTP, etc...).

For this question, assume servers are the same (with the exception of
either a 1U chassis or a 2U chassis). Same HDD (2T 7200RPM), same RAM
(16G per system), same MB, same RAID controller, etc...? The RAID
configuration of all 1U systems would be RAID1 while the RAID
configuration of all 2U systems would be RAID5 with one hot spare.

Basically, I'm trying to figure out if Gluster will perform better
with more storage nodes in the storage block or if I would be better
off consolidating the storage to a few of the systems and freeing up
the resources for the email services on the remaining systems.? I've
had mixed results testing this in a KVM virtual environment, however
it's getting down to the time where I need to make some decisions on
ordering hardware.? I do know that RAID1 and RAID5 do not compare
apples to apples for performance,? I'm looking for thoughts from the
community as to which way you would set it up.

Kind Regards,

Jason


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On 10/02/12 13:01, jason at combatyoga.net wrote:
> Basically, I'm trying to figure out if Gluster will perform better with
> more storage nodes in the storage block or if I would be better off
> consolidating the storage to a few of the systems and freeing up the
> resources for the email services on the remaining systems.  I've had
> mixed results testing this in a KVM virtual environment, however it's
> getting down to the time where I need to make some decisions on ordering
> hardware.  I do know that RAID1 and RAID5 do not compare apples to
> apples for performance,  I'm looking for thoughts from the community as
> to which way you would set it up.
With maildir, I believe that fewer bricks would perform better.  The 
maildir format tends to be readdir() heavy.  Since Gluster does not have 
a master index of directory entries, it has to hit every brick in the 
volume.

-- 
Mr. Flibble
King of the Potato People