High-Availability IMAP server

[Scott Adkins]

--On Monday, September 26, 2005 6:45 PM +0200 David <info-cyrus at mantxado.com> wrote:

> Hello,
>
> I have a 'pseudo' High Availability SMTP system consisting in two servers
> running cyrus 2.2.5.
>
> The main problem I have is that only one of the two nodes can access to the
> mailboxes in order to keep the integrity of the cyrus databases despite the
> filesystem (GFS) has support to allow to two different servers access in R/W
> mode.

I am curious about this statement... What kind of locking is being used on
GFS that prevents two nodes from accessing mailboxes without destroying the
integrity of the cyrus database?

In our environment, we have a cluster of 4 Alpha machines, two of them are
ES40's and two of them are ES80's.  They run Tru64 5.1 (TruCluster) and are
attached to an HA San using AdvFS.  All the members of the cluster can see
all the filesystems and can access all the files and directories.  We are
currently only running Cyrus on the two ES80 machines, but we could easily
run them on all four cluster members if we wanted too... we don't because
we do run other things (i.e. Sendmail) and it is better not to mix Cyrus
and Sendmail on the same machines in our environment.

That being said... the mailboxes are all available from the Cyrus servers
running on any cluster member.  We don't see any integrity issues and it
seems to run pretty good.  Since Tru64 and Alpha's are on their way out
the door, we are looking for a future solution that would give us the as
much of the same capabilities our current environment has.  This is most
likely going to include Linux, but that then means we need to find a
suitable cluster-like file system to replace AdvFS, which could be GFS.

Anyways, I am interested in the shortcomings that you guys have encountered
with reliability and integrity when trying to run an HA Cyrus server...

Thanks,
Scott
-- 
 +-----------------------------------------------------------------------+
      Scott W. Adkins                http://www.cns.ohiou.edu/~sadkins/
   UNIX Systems Engineer                  mailto:adkinss at ohio.edu
        ICQ 7626282                 Work (740)593-9478 Fax (740)593-1944
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