Using a SAN/GPFS with cyrus
prentice at rcsb.rutgers.edu
Wed Jan 21 13:37:38 EST 2004
Ken, I'm not too familiar with QFS SANs. Does that have a filesystem
interfacewhere the filesystem itself allows multiple SAN clients to
access the same filesystem, etc?
What if the 2nd system was treated as a hot spare, and would't actually
do any mailserving functions until the primary server is shutdown. (ie
the switchover wouldn't be automatic - it would require human intervention).
Ken Murchison wrote:
> Prentice Bisbal wrote:
>> I'm installing Cyrus on a ssytem that will have access to an IBM FAStT
>> SAN with GPFS (a parallel filesystem allowing multiple servers to
>> share a filesystem on a SAN).
>> For redundancy, I was thinking of creating the IMAP folder dir and
>> spool dir on the SAN and then having two mailservers setup identically
>> using cyrus. If the primary server goes down for any reason, the
>> secondary would automatically begin receiving/delivering mail based on
>> the MX records in DNS.
>> Would this present any problems with cyrus if two servers are
>> accessing the same directories/files? GPFS should manage file sharing,
>> but I'm wondering if there are any know problems with Cyrus in this
>> Has anyone done this before?
> Sharing mailboxes.db is prone to problems, if one machine trashes it,
> then the other machine(s) need to be halted while the db is
> reconstructed. I'm involved in something similar using 3 or 4 load
> balanced Sun machines on a QFS SAN. The current setup keeps separate
> mailboxes.db, deliver.db and tls_sessions.db on each machine (which
> means that duplicate delivery and Sieve aren't foolproof across
> machines). I have modified imapd and mupdate to keep mailboxes.db in
> sync across the machines. This code is currently being beta-tested, and
> I haven't heard any complaints for weeks.
> If you are interested in looking at this, checkout the unified-imapd
> branch from CVS.
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