Subject: Crashed INBOX

From: [email-masked] (Jordan D. Luttrell)
Date: Mon, 29 Jan 1996 23:40:23 GMT

I logged into PINE today, to find my INBOX had disappeared, i.e., there 
were no messages in it, even though the day before, there were.

Is there any way to recover a crash like this?

Do people back up their INBOXes, or is it in the hands of the Gods?

Many thanks,

Joe Luttrell

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From: Mike Brudenell <[email-masked]>
Date: Tue, 30 Jan 1996 09:12:39 +0000 (GMT)

This may well NOT be the solution to your problem, but is (hopefully) 
useful to someone...

We run a collection of SGI machines running IRIX.  Mail is stored on a 
disk locally attached to our mail server, which runs IMAP daemons to 
access it.  We use Pine (from UNIX) and ECSmail (from PCs) to access said 
mail over IMAP.

As a concession to the few die-hards and also to let shell mail checking 
work we also NFS mount the mailstore on each of the other IRIX systems.

Occasionally some bright spark(!) "discovers" that their mail is 
delivered slightly quicker if they send it to 
"username@name-of-current-machine" rather than "[email-masked]" (the 
latter going to our mail hub).

The result is that their mail is NOT passed to the mail hub, but the 
local machine they are using instead delivers the message into the 
recipients' mail folder (writing to the mailstore over the NFS link).

UNFORTUNATELY there is a bug in IRIX involving NFS mounted mailstores 
(possibly also more general ... I don't know).

The upshot is that the recipient's mailbox becomes inaccessible on the 
machine which delivered the message into it over NFS.  This is apparently 
to do with problems with file locking over NFS and assorted other gubbins.

The upshot as I say is that the recipients' mailbox can no longer be read 
from on the machine which delivered the message into the box over NFS.

In particular if someone tries to use a non-IMAP mail program (Elm, Pine 
not configured to use IMAP, etc) then they get either an error message or 
(as is the case with Pine) an empty INBOX presented to them.

However IMAP can be used successfully to access the folder (the IMAP 
server is running on the mail server and accessing the disk locally, so 
NFS is not involved).

The only ways we have found out of the above situation when it occurs is:

*  Wait for some sort of timer to expire, or
*  Reboot the machine, or
*  Login to another machine as root, copy the mail folder to a new file, and
   mv this back over the old one (changing its i-node and restoring access).

Our verdict:

*  Use IMAP for mail access.  It *is* good!
*  Be wary about NFS mounting your mailstore.
*  If you must NFS mount it (eg, so that sh can stat it and check for new
   mail arriving) consider exporting/mounting it read-only.

Cheers,

Mike Brudenell                                         <[email-masked]>
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