We have a medium sized environment with several discrete mail domains. The mailservers for the domains are (for historical reasons) all of a different type (HP-UX, Solaris, AIX and SGI) but are all running sendmail-8.8.8. Now in the documentation from sendmail they specificly recomend AGAINST running the mail server on a machine that is an NFS client for the user mailbox filesystem.
Is anyone out there actually doing this? With a ~500 workstation, 5 mailserver environment (we'll still have multiple different mail directories one for each mail domain)? With a mixed (HP, SUN, AIX, SGI, NEXT, Linux) environment?
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We have a medium sized environment with several discrete mail domains. The mailservers for the domains are (for historical reasons) all of a different type (HP-UX, Solaris, AIX and SGI) but are all running sendmail-8.8.8. Now in the documentation from sendmail they specificly recomend AGAINST running the mail server on a machine that is an NFS client for the user mailbox filesystem.
Stephen,
I presume that you're talking about having mbox-style mailboxes here. If you try to do this, you will run into locking problems and lose a small but measurable amount of mail -- NFS locking and cacheing just isn't up to dealing with mail delivery.
If you need to have text-based NFS-mounted client mailboxes, the only reliable option is to use a mailbox format which doesn't require locking, such as Maildir.
Nick
Nick Hilliard (nick@iol.ie) said, on [990929 13:54]:
If you need to have text-based NFS-mounted client mailboxes, the only reliable option is to use a mailbox format which doesn't require locking, such as Maildir.
Amen. The only thing I've ever seen that didn't immediately give me the willies is:
http://www.earthlink.com/about/papers/mailarch.html
Nick Hilliard (nick@iol.ie) said, on [990929 13:54]:
If you need to have text-based NFS-mounted client mailboxes, the only reliable option is to use a mailbox format which doesn't require locking, such as Maildir.
Amen. The only thing I've ever seen that didn't immediately give me the willies is:
Just for reference, I was lead author of that paper.
Running mail over NFS is doable if you're really, really careful. You will definitely want to replace the rpc.lockd locking mechanism with something better. This means modifying every program anyone uses to touch the mailbox (have to do that if you go with maildir as well).
If I understand your system and requirements, which is in doubt, I don't think this is a solution I would recommend for your situation.
Hope this helps.
We have a medium sized environment with several discrete mail domains. The mailservers for the domains are (for historical reasons) all of a different type (HP-UX, Solaris, AIX and SGI) but are all running sendmail-8.8.8. Now in the documentation from sendmail they specificly recomend AGAINST running the mail server on a machine that is an NFS client for the user mailbox filesystem.
Stephen,
I presume that you're talking about having mbox-style mailboxes here. If you try to do this, you will run into locking problems and lose a small but measurable amount of mail -- NFS locking and cacheing just isn't up to dealing with mail delivery.
If you need to have text-based NFS-mounted client mailboxes, the only reliable option is to use a mailbox format which doesn't require locking, such as Maildir.
Nick
I think that if the same NFS client does all the locking, that you are MUCH safer than if multiple NFS clients are locking and unlocking the same mailboxes.
To accomplish this, you can only let the mail server NFS mount the mail spool directory. And all access to mail must be through IMAP or POP servers running on the mail server. This means that you can't run unix mail programs that want to manipulate the user's inbox file directly, such as UCB Mail, elm, or mush. But pine and netscape are OK.
Steve Losen scl@virginia.edu phone: 804-924-0640
University of Virginia ITC Unix Support
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