> -----Original Message----- > From: synrat > Sent: Tuesday, March 09, 2004 8:25 AM
> I would like to setup some kind of high availability > configuration for Courier IMAP. > > I was wondering if anyone tried simultanous write access to a > fiber channel array that only has Maildirs. I know nobody > should dare to think of such setups with any kind of file > locking, but is Courier/Maildrop/Maildir setup so completely > 'lockless' that it would work ? This sort of thing is my bread-and-butter day job. No, it won't work. Even a little bit. At all. And it will probably kick your dog, too! What will happen is this: Host A will create a nice new file in a maildir, neatly removing the data block(s) for the file from the free list (or equivalent), updating the inode lists, etc. Host B will be fat dumb and happy... And totally ignorant of anything that host A did. Immediately host B tries to access *anything* on the filesystem, it will get stale data, and (more than likely than not) it will inform you of this staleness with a panic. What you *can* do is have the filesystem accessible to host B, but only mount it once host A is pronounced dead (itself not a trivial problem). This obviously results in a short period where service is unavailable, but SMTP as a protocol is generally good at handling temporary inaccessibility, and IMAP clients are often adequate at re-establishing connections following a disconnect. Malc. ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ courier-users mailing list [EMAIL PROTECTED] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
