> Torsten Schlabach wrote: >> > The config you would need is to use drbd to mirror the data >> > directories >> >> Is this officially supported / endorsed? > Not that I know of but someone else may have a better idea than me >> I learned that Cyrus IMAPd (for whatever reason) is quite picky on >> filesystems. From the FAQ: >> >> --- SNIP --- >> >> # Using NFS We don't recommend it. If you want to do it, it may >> possibly work but you may also lose your email or have corrupted >> cyrus.* files. You can look at the mailing list archives for more >> information. >> # Using AFS/Coda We don't recommend it. It's even less likely to work >> than NFS. If you want to do it, it may possibly work but you may also >> lose your email or have corrupted cyrus.* files. CMU's previous e-mail >> system, AMS, leveraged AFS extensively for storage (and transit) >> purposes. For various reasons it didn't scale particularly well and >> led to CMU's interest in IMAP. >> >> Cyrus was designed to use a local filesystem with Unix semantics and a >> working mmap()/write() combination. AFS doesn't provide these >> semantics so won't work correctly. >> >> --- SNIP ---- > drbd isn't a file system it works on the disk level so you can have > whatever file system on top of it. You end up with the mirrored disk > partitions on each server being identical. AFAIK it is fully posix > compliant and shouldn't have any of the problems mentioned above. >> The concept of mirroring the BerkeleyDB database files on a filesystem >> level does not sound that reliable to me. I might be wrong ... > I can see your concerns and as haven't tried it I can't comment. > However, it is at a block level with only one node able to write to the > disk so there should be no difference as far as Berkly is concerned. I've been told that recent DRBD can do active/active, which means to me that with something like GFS on top of it, you get a filesystem cluster like having a SAN with a cluster fs. What also has been discussed on this list several times is that which such shared filesystem, Cyrus works when using skiplist instead of BDB for the databases. Simon > > Regards, > > Jack Stone > > ---- > 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 > ---- 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
