Another reason I hate NFS: Silent data loss!

[Dan Bernstein]

In article <27226 at adm.brl.mil> mike at BRL.MIL ( Mike Muuss) writes:
> NFS is designed as a reliable protocol.  I have pounded more than 250
> NFS requests/sec against a fileserver, and no data loss.

In this case the 20 requests came in under 1/50 of a second (somewhat
smaller, I think, but I don't have good measuring tools). I can't
sustain this load from one Sun, but a single burst was enough to lose
data.

> Things you
> should check are the number of retransmit's you authorized in /etc/fstab,

If the number of retransmits runs out, the writing process ``should''
get an error. Otherwise the implementation is (obviously) buggy.

> the error logs on both machines (run NFSSTAT), "netstat -s",

Nope. As far as I can tell, the loss was completely silent. I'm working
on a test program to exercise the problem thoroughly; I'll post it when
it's done.

---Dan