[OpenAFS] releasing volumes automatically

[Marco Spatz]

Hi,

I've set up an OpenAFS und a 4 machines cluster, and have made replicas 
of the user's home volumes. I know, that generally, this is a bad idea, 
but I want to use this as backup the user can access without my help 
(I've mounted the readonly volumes to another mountpoint).
And now I want the AFS system to release this volumes at night, but I 
don't know how to this. Thought about writing a cronjob, but I don't 
know how do gain access as admin to get the rights to execute 'vos release'.
Is there any possibility to tell OpenAFS to release certain (or all) 
changed volumes at a certain time? Would be a great help.

Thanks for your help,

Marco