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Problem with NFS mount during high load

I get a kernel message and a failed rsync when I copy files from nfs share A to nfs share B using rsync. The message is:

nfs: too small RPC reply size (0 bytes)

When I change to using UDP I get a server timeout instead.

Any ideas how I can fix this?

Thanks for your help,
Henrik Holst, Sweden.

use the nfsstat command to look at nfs transactions, client and server statistics, network statistics. The "-o net" option will show you the number of dropped packets in relation to the total number of transactions.

check rsize and wsize, should be less than MTU.

Quote:

Originally Posted by soroccoheaven (Post 2893406)

You mean to mount with rsize=1400 if my MTU is 1500? Isn't that something that will give very poor performance? I tried it just now and the performance went down from 25-30 mb/s to 15-20 mb/s.

I will see in a few hours if it now is stable or not. I would actually like to have both performance and stability (of course!).

/Henrik Holst

Quote:

Originally Posted by holst (Post 2893458)

The errors are continuing to show up. Rsync stops and dmesg on the client which is copying from NFS server A to NFS server B shows:

Code:

nfs: server fs-6000.domain.org not responding, timed out

nfs: server fs-6000.domain.org not responding, timed out

Nothing shows up in the system log on the NFS servers.

When I look at the two NFS servers I see that they are not 100% loaded all the time (they are idle almost 100% a few seconds now and then.)

Also, the network utilization graph is not so funny

Code:

################################################################################

RX    MiB

    23.41 ...***................******........................**..****

    19.51 **.*****.........***.************..........**..***..********

    15.61 ********.........***.************..........*****************

    11.71 ********.........*****************.........*****************

    7.80 ********.........*****************.........*****************

    3.90 ********:*:*:.::******************:***::*:****************** [-0.46%]

          1  5  10  15  20  25  30  35  40  45  50  55  60 s

TX    MiB

    31.37 .*....*..........*.*............................*...........

    26.14 .**...**...*.....***................**..*...*.*****.........

    20.91 ***...**...*.....****.......***.**.***..*...*.*****.........

    15.68 ***...**.*.*...*.****.......**********..*..********.........

    10.46 ***..*******..********.....**************..********.........

    5.23 *************:***************************::***************** [-0.46%]

          1  5  10  15  20  25  30  35  40  45  50  55  60 s

################################################################################

pls. see this ..might be helpful..NFS Performance