HP StorageWorks SAN Virtualization Services Platform 2.1 release notes (5697-8060, March 2009)

name of a VSM server is allowed if two VSM servers manage the system and are both connected
to the SAN.
• Do not initiate an iSCSI connection for a VSM server to itself. Loopback is not supported.
• Only one NIC should be used as the iSCSI initiator/target on a VSM server. The other NIC is used
for management. Therefore, the iSCSI NIC could be in a private Ethernet domain used exclusively
for an SVSP domain-to-domain replication (remote mirroring).
• The VSM server is intended to be used only for VSM-related tasks. No other applications should
be installed on the server except as configured during installation (for example, Symantec AntiVirus,
Symantec Ghost, PuTTYtel, and so on).
• Do not overload the array that contains the setup virtual disks. An overloaded array is one where
the average write response time for the VSM setup virtual disk exceeds 20 msec.
• The default threshold for capacity alerts is 10%. When setting capacity alerts, you should set the
alerts slightly higher (for example, add 5%) to ensure that the storage administrator is notified in
time.
• Keep in mind that once a synchronous mirror is created, you cannot:
• Remove host permissions from a synchronous mirror group.
• Change the LU number of a synchronous mirror group.
• You cannot add synchronous mirroring to a member of an asynchronous mirror group due to the
existence of the asynchronous PiTs. However, you can first create a synchronous mirror and then
add the asynchronous mirror group to it.
• Do not mix virtual disks with both “Continue-on-fail” and “Always sync” synchronous mirror groups
in the same cluster.
Operational best practices
• Should you want to delete, remove, or undo an operation to an SVSP entity, it is best if you reverse
the processes that were used to get you to that operational stage. Additional details are in the HP
StorageWorks SAN Virtualization Services Platform administrator guide.
For example, you have I/O to a snapshot created from a PiT that was created from a virtual disk
(that is online to a different application). Assume the following steps were performed to get to this
stage:
1. A virtual disk is created from a pool.
2. The virtual disk is presented to a host.
3. The first I/O stream is initiated to the virtual disk.
4. A PiT is created from the virtual disk.
5. A snapshot is created from the PiT.
6. The snapshot is presented to a host.
7. The second I/O stream is initiated to the snapshot.
If you decide to delete the virtual disk, you should remove or halt all the operations that were
performed from the time the virtual disk was created, by working backwards. In this case the
process would be:
1. Halt the second I/O stream to the snapshot (initiated in step 7 above).
2. Unpresent the snapshot to its host (presented in step 6 above).
3. Delete the snapshot (created in step 5 above).
4. Delete the PiT (created in step 4 above).
HP StorageWorks SAN Virtualization Services Platform 2.1 release notes 7