Cyrus, clusters, GFS - HA yet again
dave64 at andrew.cmu.edu
Fri Oct 27 07:22:43 EDT 2006
Janne Peltonen wrote:
>And if further splitting of users on more servers is needed - downtime
>again. Moreover, it's confusing for the users to have to determine their
>correct imap server name - we haven't really had trouble with this, but
>it would be nice if the users saw a unified system image.
If you decide not to pursue a cluster solution, Perdition would probably
help you with this part.
>Enter weirdness. The first Cyrus to be started starts with no
>complaints and ends up with the correct number (as specified in
>/etc/cyrus.conf) of imapd, imapd -s, pop3d, lmtp etc. processes, all in
>state S, only one process at a time having a write lock on
These lockfiles are used to serialize their corresponding processes
(imap, lmtp, etc) on a per-host basis, not across cluster nodes. As
such, you should write these to the local filesystem and not the cluster
filesystem. You can accomplish this with symbolic links.
I believe you'll also need to make some minor code changes. When
University of Pittsburgh implemented their Cyrus cluster, they added a
nodename config option and then used that nodename as a filename
component along with the pid for the lmtp temporary deliver files such
that the filenames would be unique across cluster nodes. Without
modification, only the pid is used as a means to make the filenames unique.
More information about the Info-cyrus