P. Larry Nelson said...

...
|I am currently going thru and adding "udp" to all the SL4.7 clients' fstab
|entries so they will use UDP rather than TCP.
|
|My main question is, lacking any explicit protocol designation in the fstab,
|how can one tell which protocol a client is using?

You can find the tcp connections using

   netstat -a | grep nfs

or just run

   cat /etc/mtab

to see each mount.

|And lastly, why wasn't the change documented in the release notes?
|
| From what I've gleaned about the two protocols from googling, it appears
|that TCP has advantages on a lossy network but that's not our scenario.
|It also is not a stateless protocol, like UDP, so if a server crashes in
|the middle of a packet transmission, the client will hang and filesystems
|will need to be unmounted and remounted.  So it would seem UDP is better,
|at least in our case.

We found things to be much more robust, and only very slightly
slower, using tcp.  We had plenty of hangs using udp, but that
was many kernel revs and other bugs back, so who knows?

-Miles