On Thu, 17 Mar 2005, Derek Martin wrote:
> Understood. OTOH, if it is a legitimate bug, knowing about it,
> wouldn't you want to fix it?
Yes, I would. The problem here is in the knowing... :-)
> > I wonder why we have had no problems with user mailboxes on NFS (for a
> > system with three separate hosts) over the last 8 or so years, then?
>
> It could just be that you've been lucky...
>
> In all honesty, the race conditions involved are (as I understand it)
> such that should be exceedingly rare to encounter a problem.
Did I mention that we do you the lock files + link() trick? As well as
fcntl() locks. Looks like I forgot.
> It would mean that the MDA and the MUA would have to, at the exact
> same time, both request an exclusive lock on the same file, and the
> request which came over NFS came first but was interrupted before it
> completed. Even on busy mail spool files, how likely is that to
> happen?
I did say "mailboxes", not spool files. (Assuming the Exim usage of
the word "spool".) I wouldn't put a mail spool (in the Exim sense) on
NFS. But from your mention of MUAs, I guess you were meaning mailboxes.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book: http://www.uit.co.uk/exim-book
