On Wed, 9 Apr 1997, Tom Yates wrote:

we just moved /var/spool/mail from an Ultra-2 to the toasters. i wouldn't say it has been completely painless by any means, though from some angles it's been a win... dave, you want to comment further?

I do have a few thoughts and observations:

1) Writing to /var/spool/mail via the F330 (NFS) was a win for us in this case, especially once we increased NVRAM from 2MB -> 4MB. This particular F330 is used for other (general) access, not just for mbox duty. Observations lately point to the need for more NVRAM at peak times, so we're going to 8MB shortly. The box gets really humped when it's stuck in constant physical disk writes.

The old situation was a Fast-Wide SCSI disk attached directly to the UltraSPARC 1. That disk was doing way too much.

2) One of the reasons for migrating to the Toaster was to eliminate our mailhost from exporting /var/spool/mail. This enabled us to be able to do work on the mailhost/newshost without being too disruptive. The Toasters have to always be up anyway or all UNIX boxes hang.

Our current thinking is that we might do well to go to a SPARCstorage array locally attached to the mailhost and *not* exporting /var/spool/mail at all, and forcing the use of POP3/IMAP. Those people using Elm will just have to use Pine. No big loss...in fact, a big gain. But making users change email software can be a pain, especially for the zealots who insist on performing every single action from within Emacs. Don't get me wrong, I love Emacs. But sometimes you gotta draw the line.

3) If you use POP3 you will be incredibly unhappy at times, especially if even a few users have large mailboxes. This is due to the way most stock poppers do mailbox locking. (write temp file called .user.pop and then write this file out again as user)

Our current approach is to set a reasonable threshold on user mailbox sizes and email users informing them to check their mail settings and clean up. There are many variables here that relate mostly to POP settings in the client programs.

4) IMAP4 is pretty good. Use it if you can. It also solves a lot of the issues with being a mobile user. IMAP4 is better than POP3 in this respect. More like a true client-server mail package with all the benefits of having source code and not needing to open shrink-wrap.

-- Dave Pascoe | mailto:dave@mathworks.com | Voice: 508.647.7362 KM3T | http://www.mathworks.com | FAX: 508.647.7002 PGP fingerprint: 53 AD 71 88 2F AA 45 AC D0 2E 68 91 71 77 39 AF