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From Paul Richards <p...@netcraft.co.uk>
Subject Re: changes to mod_cookies.c
Date Wed, 16 Aug 1995 11:48:58 GMT
In reply to David Robinson who said
> 
> >The only flakiness I saw was that apparently solaris had problems with 
> >nfs-mounted log files - did this get addressed somewhere along the way?  
> >I know de-NFS'ing the logs made it stop hanging.
> 
> Ahh well, I'm not surprised it doesn't work; no one mentioned log files
> over NFS before. I've justed checked; 0.8.8 hangs on a restart if error_log
> is NFS mounted.
> 
> File locking on a file mounted over NFS is TERRIBLE BEHAVIOUR. Apart
> from the dire server performance this incurs, lock daemons are notoriously
> buggy.

Well, you're going to have a great deal of difficulty locking NFS files
on any of the free unices since they don't have lock daemons :-)

> 
> Apache should NEVER be trying to lock a file that is mounted over NFS.
> And this is yet another reason why the scoreboard file should not be
> in the logs directory, performance will suffer again.
> 

It's rather hard for apache to know whether a particular filesystem is
NFS mounted. It's quite possible to run apache on a diskless machine
(technically possible anyway). 

This needs to be looked at another way. If possible change the way
apache works so that file locking is not necessary, or at least
minimised. For those cases where locking is absolutely essential then
document the fact that those file should not be on NFS mounts.

You can't do any more than this, you have to rely at some point on the
ability of the admin to set things up in a way that works :-) It's not
a very sound practive to have apache's log file on an NFS server anyway
since NFS write are slow and you have to write to the logs for every hit.

-- 
  Paul Richards, Bluebird Computer Systems. FreeBSD core team member. 
  Internet: paul@FreeBSD.org, http://www.freebsd.org/~paul
  Phone: 0370 462071 (Mobile), +44 1222 457651 (home)

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