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Cluster Shared Volumes RRS feed

  • Question

  • Hiya,

    I had a CSV that was attached to all VMs. I no longer needed the CSV so I detached it from all VMs (and rebooted all VMs to be sure) and took the CSV offline.

    Only to find out all my VMs started saving and going offline. Why did this happen? In Failover Cluster Manager when I select a VM, the middle-bottom pane shows the offline CSV as still being attached to the VM, but the VM runs happy with the CSV still offline.

    Just confused really...

    Friday, November 4, 2011 10:15 AM

Answers

  • Hi,

     

    How did you detach the CSV from all VMs?

     

    As you mentioned you had one CSV for all VMs. So when you configured CSV on the Hyper-V Failover Cluster, you should have a path like C:\ClusterStorage\Volume1. I suspect that you store all your VMs with path such as C:\ClusterStorage\Volume1\VM01.

     

    If the above is true, when you don’t want to use CSV, you can remove the disk from it or disable it, then the path C:\ClusterStorage\Volume1\ will disappear. So you have to export the VMs before you do that. Or else, you will not be able to start your VMs after you disable CSV.

    Note: If you use GUID of the disk to store VMs instead of disk path such as C:\ClusterStorage\Volume1\, you will be able to run the VMs after you disable CSV.

     

    If you disable CSV in a Hyper-V Failover Cluster, you have to dedicate on LUN for a VM if you want to perform a quick migration or live migration.

     

     

    Best Regards,

    Vincent Hu

     

     

     

    Friday, November 4, 2011 2:46 PM
  • To add to Vincent.

    The Cluster Shared Volume is at the hypervisor level and the VMs are physically stored on it.  It is a single LUN that all the hypervisors share for the sole purpose of having one LUN that can store multiple VMs (and their virutal disks).

    In taking a CSV offline all the VMs that have VHDs on that CSV will (in effect) be broken.  Becuase their virtual disk resource (when you look in Failover Clustering manager) will also go offline as it has a dependency on the CSV.

    If you don't want the CSV, then you must Export your VMs to other storage before you can take the CSV offline.

    While CSV is (technically) an abstraction of a physical LUN, it becomes a dependency of the configuration.  You can't simply turn this abstraction on and off.


    Brian Ehlert (hopefully you have found this useful) http://ITProctology.blogspot.com
    Learn. Apply. Repeat.
    Friday, November 4, 2011 3:01 PM

All replies

  • Hi,

     

    How did you detach the CSV from all VMs?

     

    As you mentioned you had one CSV for all VMs. So when you configured CSV on the Hyper-V Failover Cluster, you should have a path like C:\ClusterStorage\Volume1. I suspect that you store all your VMs with path such as C:\ClusterStorage\Volume1\VM01.

     

    If the above is true, when you don’t want to use CSV, you can remove the disk from it or disable it, then the path C:\ClusterStorage\Volume1\ will disappear. So you have to export the VMs before you do that. Or else, you will not be able to start your VMs after you disable CSV.

    Note: If you use GUID of the disk to store VMs instead of disk path such as C:\ClusterStorage\Volume1\, you will be able to run the VMs after you disable CSV.

     

    If you disable CSV in a Hyper-V Failover Cluster, you have to dedicate on LUN for a VM if you want to perform a quick migration or live migration.

     

     

    Best Regards,

    Vincent Hu

     

     

     

    Friday, November 4, 2011 2:46 PM
  • To add to Vincent.

    The Cluster Shared Volume is at the hypervisor level and the VMs are physically stored on it.  It is a single LUN that all the hypervisors share for the sole purpose of having one LUN that can store multiple VMs (and their virutal disks).

    In taking a CSV offline all the VMs that have VHDs on that CSV will (in effect) be broken.  Becuase their virtual disk resource (when you look in Failover Clustering manager) will also go offline as it has a dependency on the CSV.

    If you don't want the CSV, then you must Export your VMs to other storage before you can take the CSV offline.

    While CSV is (technically) an abstraction of a physical LUN, it becomes a dependency of the configuration.  You can't simply turn this abstraction on and off.


    Brian Ehlert (hopefully you have found this useful) http://ITProctology.blogspot.com
    Learn. Apply. Repeat.
    Friday, November 4, 2011 3:01 PM