[comp.mail.sendmail] Disk quota on /var/spool/mail

mills@ccu.umanitoba.ca (Gary Mills) (04/19/91)

I'm getting concerned about the amount of disk space some users have
on our mail spool.  Enabling disk quota there would be one way to
control this.  Will anything terrible happen if I do this?  I assume
that /bin/mail will report an error and sendmail will bounce the mail.
We run SunOS 4.1.1, with NFS and NIS, if it matters.

-- 
-Gary Mills-         -Networking Group-          -U of M Computer Services-

rickert@mp.cs.niu.edu (Neil Rickert) (04/20/91)

In article <1991Apr19.163757.14374@ccu.umanitoba.ca> mills@ccu.umanitoba.ca (Gary Mills) writes:
>I'm getting concerned about the amount of disk space some users have
>on our mail spool.  Enabling disk quota there would be one way to
>control this.  Will anything terrible happen if I do this?  I assume
>that /bin/mail will report an error and sendmail will bounce the mail.

  It depends on the type of error.  It is quite possible that the error status
reported will cause the mail to go into the queue (presumably on the same
disk partition) for another attempt next time the queue is run.

>We run SunOS 4.1.1, with NFS and NIS, if it matters.

 Well, it probably does matter.  I believe that the Sun systems require the
mail spooling directory to be publically writeable, which makes it much more
difficult to control this problem.  If you can prevent a user from accessing
the mail directory, and can set up a program alias to deliver his mail to
a file in his home directory you can make this the user's problem instead of
your problem.  (Of course you should only take such drastic action for known
miscreants.)


-- 
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
  Neil W. Rickert, Computer Science               <rickert@cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115                                   +1-815-753-6940

kre@cs.mu.OZ.AU (Robert Elz) (04/20/91)

mills@ccu.umanitoba.ca (Gary Mills) writes:

>Enabling disk quota there would be one way to
>control this.  Will anything terrible happen if I do this?

/bin/mail is setuid root (generally) and root is immune from quota
restrictions, so quotas are never going to stop mail arriving for a user.

The biggest effect will be on the poor luser who reads his mail (when
its in a file bigger than the quota allows) and wants to leave it in
the mail spool file (ie: uses Mail or some other stupid mailer like that).
He will find a "write error" and half his mail gone missing.  (Advanced
lusers will keep the tmp file, and save their mail again someplace else,
then mail it all back to themselves later, so its only the naive that
really lose this way).

You aren't likely to be popular...

Quotas on mail filesystems are one of the bigger evils I can imagine.
Quotas certainly have their uses, but managing /{usr,var}/spool/mail
is so trivial without them, and they're so obnoxious there, that its
really a very poor idea.

If a message to abusers doesn't cause the problem to clear up, just
take their mail file and move it to somewhere else.

kre