Hi Miles,
Miles O'Neal wrote on 2/26/2009 2:04 PM:
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
Right, that sort of works. :-)
If a client *is* using TCP for nfs, then those connections show up.
If a client is using UDP for nfs, then nothing shows up.
or just run
cat /etc/mtab
to see each mount.
That, like running the 'mount' command, only shows the protocol *if* the
protocol has been explicitly entered in the fstab.
|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
Thanks!
- Larry
--
P. Larry Nelson (217-244-9855) | Systems/Network Administrator
461 Loomis Lab | High Energy Physics Group
1110 W. Green St., Urbana, IL | Physics Dept., Univ. of Ill.
MailTo:[email protected] | http://www.roadkill.com/lnelson/
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