nfs problem, client hangs other client when KDE starts

[Guest]

Hi,

I have a home system working with Kubuntu since 3.5 years without problem but this time, the upgrade to 12.04 is a disaster.
My home system is composed of one server (atom machine, 32 bits system) and two client (intel, 64 bits system). The /home directories are on the server (nfs) and are mounted automagically with fstab.

Until last week, everything was fine, all machine were running kubuntu 11.04 64 bits for the clients and ubuntu server 11.04 32 bits for the server. In the past, I have updated the clients at least 4 of 5 times without any big problems. Usually, I upgrade the clients every 6 months (always fresh installs) with the new kubuntu version and the server once a year. I did not upgrade the client with 11.10 because I had no time (and everything was running fine).
3 days ago, I decided to upgrade all the machines with 12.04.

First problem: At start-up, the home directory are not automounted fast like before. When the login window pops-up, I must wait around 1 minute before typing my password. It is very frustrating (never seen this in a previous version).

Second problem: if one client is working (and the second one is off), everything is fine. If the second client is turned on, both clients are freezing when KDE is booting up !!!
The system is completely unusable. The only way to bring back to life one computer is to hard reset the other one.

The problem is the same if I use nfs3 or nfs4. I was using nsf3 untill now and I have also tested with nfs4 (using this howto: https://help.ubuntu.com/community/SettingUpNFSHowTo) but the problem is the same. The only thing working is one client at a time...

Thanks to help me, I am almost desesperate...

[Guest]

Hi,

After a full week of work on the problem, I have finally found a solution.
It is looking like nfs4 is really buggy on Kubuntu 12.04, both on the client and on the server side.
The first problem has already been found by some other people and the work around was to force the client to mount nfs in version 3 with nfsvers=3 in the fstab. But this was not working because the server refused to use the version 3 of the protocol.
The second problem is probably coming from some incompatibility between nfs4 and gigabit ethernet.
The solution to all this mess was to install Debian stable on the server (to allow the server to work with nfs3) and to force the client to use nfs3 instead of nfs4.

My conclusion, nfs4 on Kubuntu 12.04 is a real mess, both on the client and on the server (I might add when using gigabit ethernet). I hope this information can help someone and avoid him to loose a lot of time looking for a fix...

[oshunluvr]

Thanks for this info. I was having a similar problem with nfs but I determined jumbo frames was causing the problem and returning to 1500 mtu made it go away. If I have future issues, I'll look into your solution again.