[672] in Info-AFS_Redistribution
Re: can I install /usr/afs/... in /var/afs/...????
daemon@ATHENA.MIT.EDU (Peter Lister, Cranfield Computer C)
Mon Mar 23 13:46:36 1992
To: info-afs@transarc.com
Cc: ccprl@xdm001.ccc.cranfield.ac.uk
In-Reply-To: Your message of Sat, 21 Mar 92 13:51:09 +0000.
Date: Mon, 23 Mar 92 15:47:29 GMT
From: "Peter Lister, Cranfield Computer Centre" <ccprl@xdm001.ccc.cranfield.ac.uk>
Steve,
Like the other answers suggest, you can put AFS binaries in /var/afs; we've been
running a system like this for over six months now. We also dkload the
libafs.a from /var/vice, having no Ultrix source license. Irritating, but it works.
However, while having /usr in AFS is great for keeping everything up-to date and
consistent, there are a few gotchas. While I think we've probably sorted most of
them, we generally found them the hard way!
DON'T ln -s /afs/cell/@sys/usr /usr after AFS has started up. Your clients run
perfectly until the server they happen to be using for /usr fail. Even if you
have replicated /usr/*, the client can't get at /usr/vice to find a new server
to try; it hangs until the original server is restored. You need a local /usr
directory containing symbolic links to directories in AFS. We rebuild a new /usr
at reboot to make sure that clients have an up-to-date /usr.
Be VERY careful with suid root binaries; if you make a new version available,
then don't simply overwrite and vos release, as it seems that the cached parts
of the old version get munged up with the new one. Normal binaries treated like
this crash with segmentation faults. Suid root binaries crash the client
instead. I put the new version in a different directory, then put the directory
in user's path (fortunately there's a systemwide .login) before the normal
directory, then wait a few days for the old binaries to be flushed out. You CAN
fs flush all your clients, but doing this with ninety of 'em is awkward.
Bear in mind that s/w vendor's installation scripts assume that /usr is mounted
locally, and that they can write to it if run by root. You need to
ensure that clients on which you install this kind of thing has /usr pointing to RW
mount points. DEC's setld is bad example of this.
I tentatively suggested a few weeks ago to Dan Nydick that putting /usr onto
AFS, and the problems / benefits found by different sites would make a
good topic for discussion at AFSUG. I'm intending to compile a report
on what we've done here. Just to gauge reaction, how many info-afs
readers would be interested
in this? If you are, reply direct to me and I'll summarise to the list.
Peter Lister p.lister@cranfield.ac.uk
Computer Centre,
Cranfield Institute of Technology, Voice: +44 234 750111 ext 3157
Cranfield, Bedfordshire MK43 0AL England Fax: +44 234 750875
