Path: utzoo!attcan!uunet!husc6!mailrus!purdue!decwrl!ucbvax!MAILGW.CC.UMICH.EDU!rees
From: rees@MAILGW.CC.UMICH.EDU (Jim Rees)
Newsgroups: comp.sys.apollo
Subject: Re: sendmail problem
Message-ID: <8808171538.AA04169@mailgw.cc.umich.edu>
Date: 17 Aug 88 15:39:23 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: rees@caen.engin.umich.edu (Jim Rees)
Organization: The Internet
Lines: 19


    Every so often, maybe a couple times a week, sendmail will not be able
    to deliver a message.  If it is able to return an error message, it will
    say "554 \dennis... unknown mailer error 1" with the accompanying
    message
          mail: cannot append to /usr/spool/mail/dennis
          mail: can't send to dennis
    or maybe just "554 \dennis... unknown mailer error 2".
     
    On some of these occasions, the error seemed to occur at about the time
    a user was getting out of mail, or using the command "file %" to update
    the mail file.  At other times, this wasn't the case.

Just a guess, but if your local user agent (ucb mail) has /usr/spool/mail/dennis
locked for reading, then a delivery agent (/bin/mail) on another node tries
to open the spool file for writing, it won't be able to acquire a write lock
and it may give up.  What it should do is retry in a few seconds, but I
don't know if the domain/ix /bin/mail does this or not.
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