3PAR VSS Provider for Microsoft Windows 1.6 User's Guide

4.3
3PAR VSS Provider for Microsoft Windows 1.6 User’s Guide
4.2 Special Considerations
■ Auto-Import Shadow Copies are not supported on Windows Cluster service.
Windows Cluster service cannot accommodate LUNs with duplicate signatures and partition
layout. The shadow copy LUNs must be transported to a host outside the cluster, or the
original volume must be dismounted before the shadow copy can be imported. This is a
limitation of the Window Cluster service.
■ Shadow Copies Containing Dynamic Disks must be Transported.
The native support for dynamic disks cannot accommodate LUNs with duplicate signatures
and configuration database contents. The shadow copy LUNs must be transported to a
different host. VSS enforces this by not allowing auto-import shadow copies of dynamic
disks. A requestor should not import a transportable shadow copy back to the same host.
This is a limitation on Dynamic Disk.
■ Create Shadow Copy Volumes Read-Only and Hidden.
VSS sets flags on each affected LUN such that the resulting shadow copy will be hidden and
read-only when detected by a Windows Server 2003 or 2008 system. Drive letters and/or
mount points are not automatically assigned. VSS maintains these flags throughout the
lifecycle of a shadow copy. Modification of these flags may lead to unpredictable results.
■ Shadow Copy Attribute Context.
The following are shadow copy attributes supported by passing in the shadow copy
context:
◆ The shadow copy is persistent across reboots.
◆ The shadow copy is not automatically deleted when the shadow copy requestor process
ends. The shadow copy can be deleted only by a call to:
IvssBackupComponents::DeleteSnapshots.
◆ No writers are allowed in creating the shadow copy.
◆ The shadow copy is currently not exposed to the requestor.
◆ A copy-on-write mechanism is used to implement shadow copies.