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Unable to use Snapshots or perform a backup on virtual machines configured with bus-sharing (1006392)
When working with a combination of Raw Device Mapping (physical or virtual), Microsoft Clustering (MSCS), Snapshots,Consolidated Backup, and/or Data Recovery, you may experience these symptoms:
- Cannot take a snapshot
- The snapshot feature does not appear to be available on virtual machines and the option is greyed out
- When attempting to set a SCSI controller to shared, you may see an error similar to:
Device 'SCSI controller 1' is a SCSI controller engaged in bus-sharing.
When attempting to create a snapshot, the operation may fail with the error:
Snapshot creation failed: Virtual machine is configured to use a device that prevents the snapshot operation: Device '' is a SCSI controller engaged in bus-sharing.
Consolidated Backup (VCB), Data Recovery (vDR), Microsoft Clustering (MSCS), Snapshots, and Raw Device Mappings(RDM) all have their own limitations and requirements that need to be adhered to. The following are a list of requirements:
- VMware Consolidated Backup requires the use of snapshots to create a backup.
- VMware Data Recovery requires the use of snapshots to create a backup.
- Microsoft Cluster nodes that exist across different physical hardware require virtual controllers to be in bus sharing configuration.
- Snapshots of a Microsoft Cluster node virtual machine using the Microsoft iSCSI Initiator to connect to storage is not supported.
- Snapshots are not supported on Physical mode Raw Device Mappings.
- Snapshots are not supported on disks connected to controllers configured for bus-sharing configuration.
Based on the above limitations, we can make the following conclusions:
- Microsoft Clustering requires bus-sharing and therefore cannot be used in conjunction with use Consolidated Backup, Data Recovery, or Snapshots.
- Virtual machines with a Raw Device Mapping in physical mode cannot be used in conjunction with use Consolidated Backup, Data Recovery, or Snapshots.
For more information, see:
If you require bus-sharing:
- Consider running backup software within your guest operating system as an alternative solution.
- If your virtual machine currently has snapshots and it is preventing you from configuring bus-sharing, delete the snapshots. For more information, see the Using Snapshots section of the vSphere Basic Administration Guide for your version of VMware ESX.
Note: If snapshot consolidation fails, see Consolidating Snapshots(1007849).
If you do not require bus-sharing:
- If your virtual machine is currently configured with bus-sharing, but you want to create snapshot, you must disable bus-sharing. For more information, see the Managing Mapped LUNs section of the ESX Configuration Guide for your version of VMware ESX.
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