[DRBD-user] Migrating NFS to a DRBD block device

Philipp Reisner philipp.reisner at linbit.com
Fri Oct 15 09:51:18 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Friday 15 October 2004 05:59, Omar Kilani wrote:
> Hello, World,
> I'm in the process of moving my RHEL3 based NFS server onto DRBD.
> Setup and configuration is fine, replication works, etc.
> Unfortunately, if I stop the NFS service, remount the block device on
> which NFS exports from onto DRBD, and start up again, my NFS clients
> start receiving 'stale file handle' errors. AFAICS, this should work,
> since NFS has no inherent tie to the lower level device -- it sits on
> top of the file system, after all.
> Stopping NFS, unmounting from the DRBD block dev, remounting the lower
> level device and starting NFS again gets things working on the client
> side. So I was wondering what the problem could be?

As far as I know NFS uses the device number and the inode number to 
identify files it its communication protocol. Since you unmont
it from the lower device and mount it on the DRBD device your inode 
numbers stay the same, but suddenly you have got an other device number.

Is this an clear explanation of the issue ?

> I'm using an *external* meta data device.
> Oh, one last question. I've got:
>     wfc-timeout  60;
>     degr-wfc-timeout 120;    # 2 minutes.
> yet, when the drbd initscript runs, it just waits forever (although the
> message does say "the timeout for resource X is 60 seconds"). I'm
> obviously missing something... I haven't used drbd in production since
> 2001 (version 0.5.8 is still running well... :) so I'm probably not up
> with the latest configuration syntax. :)

Note1: degt-wfc-timeout should usually be smaller than wfc-timout.

But yes, it should only wait 60 (or 120) seconds. Maybe you have other
resouces with an infinit wfc-timeout ?

: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :

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