On Mon, Jan 29, 2007 at 04:14:33PM -0800, Tom Samplonius wrote: > > ----- "Simon Matter" <simon.matter@xxxxxxxxx> wrote: > > > > Believe it or not, it works and has been confirmed by several peoples on > > the list using different shared filesystems (VeritasFS and Tru64 comes to > > mind). In one thing you are right, it doesn't work with BerkeleyDB. > > Just switch all your BDB's to skiplist and it works. This has really been > > discussed on the list again and again and isn't it nice to know that > > clustering cyrus that way works? > > Yes, useful. But the original poster wanted to combine Cyrus > application replication with a cluster filesystem (GFS > specifically). It seems pretty unusual to combine both. GFS has a > lot of locking overhead of writing, and e-mail storage is pretty > write intensive. And Cyrus replication can have its own performance > issues (slow replication that never catches up). Why do both at the > same time? The reason to use a clustering FS: if it works, it is very simple. Each node can be more or less identical. And, therefore, more or less redundant. And the system is scalable (just add a node), to the point where the GFS locking overhead begins to be the bottleneck. And HA is simple: if you want to do maintenance a node, just get it offline - nobody'll notice. The reason to use replication: The "master" cluster has but one filesystem. Of course it's on a SAN, RAID, blah. But if the SAN fails - such a thing happened a couple years ago, even SANs fail - we lose all mail received since last backup. Not nice. (But if combining these two really result in severe performance losses, we might have to reconsider.) > And GFS 6.1 (current version) has some issues with large directories: > > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=214239 This might be a problem, since we have some users that really have 10000 messages in their INBOX. Although it seems that Cyrus itself cannot cope with this either... in our current, non-clustering setup. But then, it's an old version. --Janne ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
