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:[log in to unmask] | http://www.roadkill.com/lnelson/ ------------------------------------------------------------------- "Information without accountability is just noise." - P.L. Nelson