It's nice to hear I'm not the only one who's run into the hang with the 2.4 kernel, though it sounds like we get it more consistently. I've seen the same issue on a RedHat 6.2 box that's updated to the 2.4 kernel, which is why I'd point to something in the kernel rather than something RedHat-specfic. The best workaround seems to be using TCP to mount the NFS shares - that should allow for better performance than limiting readand write sizes to 1023. To do that, add "tcp" to the mount options, either in /etc/fstab or using the -o flag for "mount". You'd also need to turn on the nfs.tcp.enable option on the filer.

Jered

Steve Losen scl@sasha.acc.virginia.edu@mathworks.com on 10/18/2001 10:25:54 AM

Sent by: owner-toasters@mathworks.com

To: toasters@mathworks.com cc: Subject: Re: ONTAP with RedHat linux

I am running RedHat 7.1 and NFS mounting a netapp F820 running 6.0.1R3. Things work pretty smoothly, but I have experienced the same problem as another poster (sorry, lost the message) where NFS writes occasionally delay and a "NFS server not responding" error is logged. I have not tried the rsize=1023,wsize=1023 work around.

I have experienced the same problem with NFS servers other than Netapp, including a IBM RS6000 running AIX.

Non Linux NFS clients are having no delay problems with the Netapp filers, so I'm pretty sure it is on the Linux end.

For awhile I thought the NIC on my Linux box had botched the speed/duplex negotiation with the ethernet switch. Our network folks can tell me what speed the switch port has negotiated, but I don't know how to check my NIC from Linux. The network folks tell me they see no errors on my switch port when I experience NFS delays. I don't seem to have any other network problems, so I doubt this is the problem.

I have been able to duplicate the problem on a second Linux box. However, on a third box, essentially identical to mine and also running RH 7.1, I could not duplicate it.

A couple of things to be aware of with RedHat Linux and NFS.

Prior to RedHat 7.0, only NFS v2 was supported. Furthermore, Linux only supported 16 bit uids and gids. We have a lot of files on our Netapp filers with uids greater than 65535.

RedHat 7.1 supports NFS v3 and 32 bit uids and gids. 32 bit uids are critical in our environment. I administer our filers and when I was running RH 6.2, I could not get accurate file owner information with "ls" and I could not "chown" files to uids over 65535, so I had to use another unix box for filer administration. Now I can do it all from my Linux box.

Steve Losen scl@virginia.edu phone: 434-924-0640

University of Virginia ITC Unix Support