I ran into a problem with my network on a regularly-update FC2 system. Here's my current setup:

I have three operating systems on three computers: RH7.3, FC1, and FC2. All three are using available DHCP and NIS support for hostnames and network configuration.

All three systems are acting as NFS servers, serving a partition for general data collection. Each system mounts the data disks from the other two.

I create a large file (75 ~ 89MB) on each system. Here are the times to copy files:

From the FC2 (75MB):
To FC1 via NFS 9 sec
To FC1 via scp 9 sec
To RH7.3 via NFS 7 sec
To RH 7.3 via scp 9 sec

From the FC1 (75MB):
To FC2 via NFS 7 sec
To FC2 via scp 10 sec
To RH7.3 via NFS 7 sec
To RH7.3 via scp 7 sec

From the RH7.3 (89MB):
To FC1 via NFS 11 sec
To FC1 via scp 11 sec
To FC2 via NFS 49 minutes, 6 sec (almost 3000 seconds!)
To FC2 via scp 12 sec

What can possibly be the problem with the RH7.3 -> FC2 transfer via NFS?
During the transfer the ie0 is running at 100%, but ifconfig reports no errors on the device.

Thanks for any suggestions on what to check (and details on how to check it!.

--Jim

I think I've isolated the root of the problem. I tried a few more searches on this site and came across a post that suggested udp might be the source of the slowdown.

So using rpcinfo I found that whereas FC1 and FC2 nfs servers provide ports (2049) for udp and tcp, the Red Hat 7.3 nfs server only provides ports for UDP. I changed the fstab entry on the RH7.3 system for rsize and wsize to be 512. That made all the difference: The file transfer that took 2,946 seconds last night took only 9 seconds this morning. I changed the size to 1024 and the delays came back (although not as severe as before).

So I isolated the problem and, more importantly, I have a fix. Although no one resoponded directly to me I did find the info I needed on this site, so thanks to all the people who inadvertently helped me!

Can someone answer this: What has changed in NFS support to cause this problem between FC2 and RH7.3? Why does it not manifest between FC1 and RH7.3?

Just curious.

-- Jim