On Wed, 8 Nov 2006, Brian Thompson wrote:
True, but the bigger picture is that in our environment there are many other uses for the user's home directory besides email. So, I don't foresee NFS going away anytime soon. One option might be to patch c-client such that the mix folders can use something like /var/mix/username/INBOX/ instead of ~/INBOX/ .
Alternatively, if the IMAP servers have their own filesystem, then it doesn't matter if the mailboxes are in the users' home directories on the IMAP servers.
That way the mix folders would be local without having to worry about creating a separate secondary set of local/non-NFS home directories for all of the users just for use on the email server.
I fail to see the savings. You have the same number of directories either way, only now you have to have multiple algorithms to identify a user's space.
The way that you get into trouble is when you try to get one box to assume multiple roles: an IMAP server doing tasks that are not IMAP-related, an NFS server providing both file and IMAP backend services, etc.
Separate your services onto separate hardware! That's how you eliminate single points of failure.
Another option would be to move imapd to the NFS server itself, but in my opinion that's worse than moving the mail folders over to what's currently the single NFS client serving email applications.
IMAP and NFS service on the same machine have been done. In terms of IMAP reliability and robustness, it is MUCH better than the IMAP server accessing its data as an NFS client.
However, such a configuration is a wretched compromise, suitable only for small sites. Although it's reliable and robust, its performance is not particularly good. IMAP and NFS access the filesystem in very different ways.
It would raise the question of sendmail, the local delivery agent, spam filtering, virus filtering, and DNS MX records. Which ones would move or be duplicated on the NFS server and which ones would stay on the NFS client. Optimally I'd rather keep the NFS server handling users' home directories and the email server handling email.
That is the correct position to take. The missing part of the key is that the NFS server should be out of the email business entirely, and dedicate itself for the task of serving user files.
-- Mark -- http://panda.com/mrc Democracy is two wolves and a sheep deciding what to eat for lunch. Liberty is a well-armed sheep contesting the vote. _______________________________________________ Imap-uw mailing list [email protected] https://mailman1.u.washington.edu/mailman/listinfo/imap-uw
