[gpfsug-discuss] CES - samba - how can I disable shadow_copy2, i.e. snapshots

[Jonathan Buzzard]

On 09/11/2018 12:46, Billich Heinrich Rainer (PSI) wrote:
> Hello,
> 
> we run CES with smbd on a filesystem _without_ snapshots. I would
> like to completely remove the shadow_copy2 vfs object in samba which
> exposes the snapshots to windows clients:
> 
> We don't offer snapshots as service to clients and if I create a
> snapshot I don't want it to be exposed to clients. I'm also not sure
> how much additional directory traversals this vfs object causes,
> shadow_copy2 has to search for the snapshot directories again and
> again, just to learn that there are no snapshots available.
> 

The shadow_copy2 VFS only exposes snapshots to clients if they are in a 
very specific format. The chances of you doing this with "management" 
snapshots you are creating are about ħ, assuming you are using the 
command line. If you are using the GUI then all bets are off. Perhaps 
someone with experience of the GUI can add their wisdom here.

The VFS even if loaded will only create I/O on the server if the client 
clicks on previous versions tab in Windows Explorer. Given that you 
don't offer previous version snapshots, then there will be very little 
of this going on and even if they do then the initial amount of I/O will 
be limited to basically the equivalent of an `ls` in the shadow copy 
snapshot directory. So absolutely nothing to get worked up about.

With the proviso about doing snapshots from the GUI (never used the new 
GUI in GPFS, only played with the old one, and don't trust IBM to change 
it again) you are completely overthinking this.

JAB.

-- 
Jonathan A. Buzzard                         Tel: +44141-5483420
HPC System Administrator, ARCHIE-WeSt.
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG