Robinson Maureira Castillo wrote: > Rainer Duffner wrote: > > GFS is supposed to have a smaller overhead, compared to NFS. > > However, I'm not sure this pays out in case a maildir-mailstorage is > > clustered. > > In my personal experience using GFS on RHEL4 vs NFS, is that GFS > outperforms NFS on a mail system, both using maildir and mbox style > mailboxes. > I don't know how Communigate actually delivers mail. For qmail, the problem is that it delivers into a "tmp"-directory in the user's Maildir first, then moving it to "new", and then moving it to "cur", if it was seen by the MUA. I must admit that I don't know about GFS6.1, but with GFS6, this is awfully slow, because everytime the mail is touched, a lock needs to be aquired, thus multiplying the I/O needed. I would expect a speed-up with RHEL4, but the principal problem remains, IMO. > The email software we're using is CommuniGate Pro, which doesn't do any > locking at filesystem level. > It doesn't need to - DLM will do that. Qmail also doesn't care about locking - it's from the old days, when locking didn't work anyway, so it was built to work around this problem ;-) But DLM (and GULM anyway) doesn't know that - it makes sure that no other process will write to the file at the same time (which doesn't happen anyway, qmail creates unique filenames for every mail), thus wasting a lot of I/O (and slowing deliveries into the same maildir). That, or somebody correct my assumptions.... cheers, Rainer -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
