On Thu, May 03, 2007 at 05:08:52PM +0200, Paul Dekkers wrote: > I recently tried to use NFS (on a RedHat client, both to a NetApp filer > as well as a RedHat NFS server) and I'll share my experiences: > > Michael Menge wrote: > > Cyrus has 2 problems with NFS. > > > > 1. Cyrus depends on filesystem locking. NFS-4 should have solved this > > problem > > but i have not tested it. > > > > 2. BerkleyDB uses shared Memory which does not work accros multiple > > servers. > > I used skiplist in the tests (default with Simon's RPM), and initially > just used NFSv3 (and I also tested NFSv4): as long as I mounted with the > -o nolock option it actually worked quite well (also on NFSv3). The > performance was even better with the NetApp as target than with a local > filesystem (and NFSv3 was faster than v4). > > The nolock options does not disable locking (as I understand it) for the > filesystem, it just disables locking over NFS, so other nodes won't have > the same file locked. (Correct me if I'm wrong.) My intention was not to > have an active-active setup, so in that regard this might not be that > bad. Not sure what other catches there are though. Are you try metapartition* options? If you don't need active-active setup it can be useful. > I stressed the setup with the imaptest tool from Dovecot, I saw problems > with that in the past (also with NFSv3 and v4, but in combination with > Cyrus 2.2 and I'm not sure if I tried nolock), now it seemed to do just > fine. Only NFSv4 does not seem to be the answer, it seems that -o nolock > is (on Linux as client). > > I'm very hesitant to put this into production, I just wanted to do some > more tests and ask others after that if they think this is wise or > not... I couldn't find the time to do more tests... (like see how RedHat > 5 behaves instead of RedHat 4, if the tric also works on FreeBSD, if I > can make it fail one way or another... suggestions always welcome...) On FreeBSD you can use gmirror+ggated for mirroring disk partition between servers. WBR. Dmitriy ---- 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
