Re: [Networker] How to query for whether a volume is mounted?

2008-05-06 13:01:18
Subject: Re: [Networker] How to query for whether a volume is mounted?
From: MIchael Leone <Michael.Leone AT PHA.PHILA DOT GOV>
Date: Tue, 6 May 2008 12:55:22 -0400
Davina Treiber <Davina.Treiber AT DOT uk> wrote on 05/06/2008 

> MIchael Leone wrote:
> > I have a script that deleted cloned savesets, and frees up disk space, 
> > adv_file devices (I only have enough disk space for one days's backup, 
> > every day, we run scripts to delete data off the adv-file disk device, 

> > that has been cloned to tape [i.e., copies=2]). Problem is, some of my 

> > clients are virtual servers, on a cluster (Win2003). 
> > 
> > So sometimes the disk device is mounted on NODE1, and the volume is 
> > NWSERVER.001.RO, and sometimes the disk device is mounted on NODE2, 
and so 
> > the volume is NWSERVER.002.RO, depending on which node is hosting the 
> > virtual server. And only 1 volume is mounted at a time, of course.
> > 
> > So I'd like to query NW, and ask which one of those 2 volumes are 
> > and issue a "nsrstage -v -C -V %tapevol%" accordingly.
> > 
> > Thoughts? I can't seem to figure out how to do this. this isn't a 
> > query, but I don't know what type of query it is.
> You're approaching this all wrong. Why are your storage node devices 
> defined on physical servers when they relate to virtual services? 

On Windows, you define the cluster resource (i.e., the disk drive, which 
is on my SAN), and then assign it to a virtual server. This virtual server 
is then "owned" by a specific physical node. And only the "owner" of the 
resource sees it.

So if "SAN2" has a resource of drive X:, and it's hosted on ADMNSAN002, 
then node only ADMNSAN002 sees it.

This is the way that EMC told us it *had* to be (on Windows), and they set 
it up this way.

Actually, they wanted each physical node to be a storage node, requiring 2 
storage node licenses, double space on the SAN, etc. We wanted it just for 
the virtual server in the cluster, as you suggest. So, when the virtual 
server moves from one to the other, I have to manually dismount the 
NetWorker defined volume for the node, and then mount the other NetWorker 
defined volume, for the other node.

This is the way that EMC said storage nodes on clusters work on Windows, 
if you don't have disk space defined for each physical node (as a storage 
node). Believe me, we wanted it your way. :-)

> Surely this causes you a problem of not being able to access the disk 
device on 
> the passive node? 

Not at all. :-) The passive node is just sitting there, and does not 
access the disk device. As far as it knows, the disk device does not 
exist, since the disk device is assigned to the virtual server, and the 
passive node is not hosting the virtual server, nor any of the virtual 
servers resources..

> Why not just define the disk device on shared storage 
> under the name of the service and then the volume will be the same 

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