On 03/23/10 07:43, Brian Candler wrote:
On Tue, Mar 23, 2010 at 05:42:02AM -0400, Charles Marcus wrote:
On 2010-03-22 9:31 PM, Stan Hoeppner wrote:
Dovecot has built in locking support for NFS storage.
But it has always been problematic, according to Timo.
Have you got any references on this, apart from http://wiki.dovecot.org/NFS ?
I'm looking at migrating a courier-imap installation (FreeBSD frontends, Netapp backends, Maildir++) to dovecot. I'd be grateful of any known pitfalls I should be looking out for.
I have done some small-scale testing and it looks fine. tcpdumping the NFS traffic, I see that the FreeBSD frontend is sending "access" requests to check that its local cache is not stale. In tests with mailboxes containing 100 messages and a web IMAP frontend (atmail.org), Dovecot was generating about 1/4 of the total NFS traffic compared to courier-imap, because of how Dovecot creates a cache file containing the message headers.
I see a link to http://www.freebsd.org/cgi/query-pr.cgi?pr=123755 in the NFS wiki page. Does this problem affect only mbox over NFS, or maildir too?
I've not observed any problem with courier-imap, although courier-imap is much dumber about caching, and also at the moment the majority of the userbase are on POP3 anyway.
Regards,
Brian.
I've used:
mmap_disable: yes mail_nfs_storage: yes mail_nfs_index: yes
on FreeBSD 6/7/8 and dovecot with multiple servers accessing the same mailboxes over NFS on a NetApp and it has worked fine since 1.0.16 or so, I think. I use 1.1 now (haven't finished testing 1.2 and haven't done much with 8.x). I have a load balancer in front and it sends IMAPS connections or HTTPS connections (making local IMAP calls) to randomized servers so even one person making 5 connections gets a speed benefit by using more than one server.
If the NFS support had problems you could also use mail_location to keep indexes local.