Tom Horsley wrote:
What kind of problems do you see? It can be hard to get firewall
openings right and it depends on uid's matching at the client and server
for file ownership and permissions, but those things either work right
or not at all. You shouldn't see reliability or performance problems
unless you have hundreds of busy clients.
What I mostly see is every imaginable problem on different machines
at different times :-).
I think the root cause is related to having vast numbers of different
versions of unix/linux on different machines all of which claim
to "support" NFS, but which together are highly unreliable (especially
the ones too old to support tcp connections).
Yes, there were a lot of bad implementations, but usually there were
enough other things wrong with those system that you'd have replaced or
updated them by now anyway.
The worst problem is data corruption on writes, especially writing
large files across NFS, they will often wind up with large chunks of
zero bytes in place of the actual data.
Hmmm, this sounds more like a locking issue. Did you have multiple writers?
There is one particular machine (in theory running the same dadgum
version of linux as several others) where some sort of nonsense
persists in always getting stale NFS filehandle messages any time
I try to read specific individual files. I always have to unmount
and remount the filesystem when it gets like this. (Neither system
was down or not talking at any point, just some fiddling of the
files in question, replacing them with symlinks, then suddenly the
stale filehandle messages start).
Open files are cached on the client - renaming stuff on the server while
a client has it open could cause some odd results.
The protocols are in theory supposed to support negotiation of the
correct NFS version when connecting to older machines, but that
almost never works, we have to manually fiddle fstab entries to
explicitly give the proper nfsver option or we get things like
the filesystem is "mounted" but all attempts to access files get
errors.
Herding cats has got to have fewer irritations than using NFS :-).
I don't suppose you could cut down on the number of versions that have
to co-exist... Or at least get it down to one or a few server types.
--
Les Mikesell
lesmikesell@xxxxxxxxx
