We seem to be increasingly hit by this bug:

https://access.redhat.com/solutions/2040223
“On RHEL 6 NFS client usring kerberos (krb5), one user experiences slow write performance, another does not”

You need a RH subscription to see that in its entirety. But the subject basically says it all: randomly, one or more users will be subjected to *terrible* NFS write performance that persists until reboot.

There is a root cause shown, but that is cryptic to non-kernel devs;
it doesn’t explain from a user perspective what triggers this state.
(That’s why it appears to be random to me.)

There is no solution or workaround given. This appears to be on a per-user + per-server basis, so a crude workaround is to migrate the user to a different server. And we do regular reboots, which somewhat hides the problem.

My question to the list: has anyone else dealt with this? The link says “Solution in Progress”, but that was last updated nearly a year ago. We don’t have any support contracts with upstream, just the website access subscription, so I doubt RH will offer any help. Appreciate any suggestions!

Thanks, Matt