Cyrus, NFS and mail spools

Ken Murchison ken at
Tue Sep 7 16:36:10 EDT 2004

Jure Peèar wrote:

> On Tue, 07 Sep 2004 09:10:59 -0600
> "Terry.Poperszky" <Terry.Poperszky at SOSStaffing.Com> wrote:
>>With Courier, I have the ability to spread access to the mail spool 
>>directory across several incoming smtp servers, is Cyrus able to do 
>>something similar? What I am referring too, is having multiple incoming 
>>email servers, with their mail spools being NFS mounts to a single box 
>>using Maildir format, access to which is served by courier Imap. This 
>>configuration belongs to a local ISP and I am looking at porting it to 
>>my corporate network, but I want to look at other options than Courier.
> With cyrus 2.3 branch in CVS it *might* be possible to store mails
> themselves on the NFS. The problematic part with NFS are indexes and locking
> they need; in 2.3 branch indexes can be split to a separate "metadata"
> partition which can be local.
> Of course this still does not bring you the possibility of many cyrus
> instances on separate machines using the same mail spool over NFS. As i see
> it, this would still require some established mechanism to update indexes on
> all machines in a consistent manner. One of the possibilities is to just
> rebuild them when they not match the actual state of the mailbox, as i
> understand the Dovecot is doing. How costly would that be in terms of I/O
> and/or cpu?

As far as I'm concerned, NFS still is not an option for Cyrus for all of 
the reasons that have been outlined in the past.  Cyrus 2.3 *might* work 
with NFS, but I'm not making any guarantees.

Cyrus *will* work with a shared filesystem on a SAN, provided it has the 
correct file locking and memory mapping semantics.  I know that Sun's 
QFS and SGI's CXFS both do, I'm not sure about Redhat's GFS.

Kenneth Murchison     Oceana Matrix Ltd.
Software Engineer     21 Princeton Place
716-662-8973 x26      Orchard Park, NY 14127
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