HPP Enterprises P4000 SAN - Manual (Page 50)

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Figure
43. Snapshot rollback
It is a best practice to disconnect from the storage repository and reattach to the new rollback storage
repository; however, as long as the virtual machine is in a shut down state, the volume may simply be
rolled back and virtual machine restarted to the previous state to the rolled back volume. The proper
method (best practice) will be to disconnect the iSCSI session with the old volume first by first
highlighting the Storage Repository in the XenCenter, right clicking and selecting Detach Storage
Repository (see Figure 44). In the CMC, select the volume, right click and select Rollback volume. In
XenCenter, highlight the grayed out storage repository, right click and select Reattach Storage
Repository. Re-specify the iSCSI target portal, Discover the correct IQN appropriate for the rolled
back storage repository, Discover the LUN, and select Finish. Ensure that Yes is selected to reattach
the SR. In this manner, the iSCSI session is properly logged off to the storage target, the connection is
broken while the storage is rolled back to the previous state, and the connection is re-established to
the rolled back volume. The virtual machine may once again be restarted and will start in the state as
represented by the iSCSI volume at the time of the original snapshot. See Figure 44.
Figure 44. Snapshot rollback continued
Reattach storage repositories
For new XenServer Hosts or resource pools recovering Storage Repositories, a special process exists
in order to match a storage state to a virtual machine’s virtual disk. In this example, an iSCSI volume
contains a storage repository and virtual disk’s virtual machine state, however, no configuration exists
on the XenServer Host or resource pool. Select new storage as if attaching to a new storage
repository. Of virtual disk storage type, select iSCSI type and provide the intended name. In this
example, the iSCSI volume XPSP2-05 and virtual disk has been forgotten. The name specified will be
XPSP2-05. Provide the iSCSI target portal VIP address, discover IQNs and select the XPSP2-05
volume, discover LUNs and finish. If a valid XenServer formatted volume exists, a warning indicating
that an existing SR was found on the selected LUN. Select the option to Reattach to the storage to
preserve the data currently existing on that volume. See Figure 45.