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rapideyeag
05-May-2015, 12:18
We got sometimes a kernel messages with nfsv4 shares

NFSv4 callback reply buffer overflowed


Apr 29 11:45:47 server01 kernel: [ 193.283103] RPC: Registered tcp NFSv4.1 backchannel transport module.
Apr 29 14:21:35 server01 kernel: [ 9525.728830] NFSv4 callback reply buffer overflowed!

How big is the reply buffer?
Can we increase the buffer?

Is this a problem on client or on server side?

The nfs server is a netapp filer (ontap 8.1) which have read delegation (nfs 4.1) feature on.

kernel version:
Linux ams01 3.0.101-0.47.52-default #1 SMP Thu Mar 26 10:55:49 UTC 2015 (0e3c7c8) x86_64 x86_64 x86_64 GNU/Linux

Repository: SLES 11 SP3 Updates
Name: nfs-client
Version: 1.2.3-18.38.41.1
Arch: x86_64
Vendor: SUSE LINUX Products GmbH, Nuernberg, Germany

jmozdzen
05-May-2015, 12:46
Hi rapideyeag,


We got sometimes a kernel messages with nfsv4 shares

NFSv4 callback reply buffer overflowed



How big is the reply buffer?
Can we increase the buffer?

Is this a problem on client or on server side?

The nfs server is a netapp filer (ontap 8.1) which have read delegation (nfs 4.1) feature on.

kernel version:
Linux ams01 3.0.101-0.47.52-default #1 SMP Thu Mar 26 10:55:49 UTC 2015 (0e3c7c8) x86_64 x86_64 x86_64 GNU/Linux

Repository: SLES 11 SP3 Updates
Name: nfs-client
Version: 1.2.3-18.38.41.1
Arch: x86_64
Vendor: SUSE LINUX Products GmbH, Nuernberg, Germany

from what I can tell, this "buffer" is part of the RPC structure transmitted from the server to the client, and the error message results from a decode problem on behalf of the client. Hence, this is nothing you can influence on user-side. These symptoms (decoding XDR structures) can either point to a server-side problem when filling the data structures, but can as well occur when client and server side implementations differ WRT to the actual XDR message structure. So it *could* be an issue of (NFS) implementation version mismatches.

Anyhow, I strongly recommend to open a service request so a SUSE engineer can have a detailed look into this.

Regards
Jens