[Pacemaker] nfsv4 grace period

[Dennis Jacobfeuerborn]

On 09.02.2014 08:33, Michael Schwartzkopff wrote:
> Am Sonntag, 9. Februar 2014, 02:56:55 schrieb Dennis Jacobfeuerborn:
>> Hi,
>> i have setup a nfsv3 HA cluster before and that works fine but now I'm
>> trying to move to v4 and run into problems with the lease grace period.
>> The grace period on CentOS 6 is 90 seconds and that limits how quickly
>> the fail-over can happen. The file /etc/sysconfig/nfs contains a
>> variable NFSD_V4_GRACE to control this but it doesn't get applied. The
>> reason is that the file /proc/fs/nfsd/nfsv4gracetime is not writable:
>>
>> [root at nfs1 init.d]# echo 10 > /proc/fs/nfsd/nfsv4gracetime
>> -bash: echo: write error: Device or resource busy
>
> You can write the paramerter only after the nfsd kernel module is loaded. As
> far as I can remember the init script sets the leasetime according to the
> config. You have to add a config option and patch your init script to set the
> gracetime at the same point in the script.
>
>> Does anyone know what the proper way is to reduce this value?
>
> In RHEL 6.5 it is a option in the config file.

Yes this is the NFSD_V4_GRACE option in /etc/sysconfig/nfs I was 
mentioning above and in the init script this gets set right after the 
kernel module is loaded but this doesn't seem to work. When I uncomment 
this option and set it to 10 seconds after the service is started the 
value for the grace time is still 90 for /proc/fs/nfsd/nfsv4gracetime.
I've also looked for a parameter for the kernel module itself to set 
this when the module is loaded but that doesn't exist and now I'm 
wondering how to set this value at all.

Do you know what the criterion is that determines when this value is 
settable? The module is loaded the whole time so that alone can't be the 
only factor here and there must be some additional constraint that now 
prevents me from updating this value.

Regards,
   Dennis