HP MPX200 Multifunction Router - Manual (Page 142)

Choosing the right DMS options
Follow these guidelines when choosing DMS options:
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Use the Configure Only option to configure migration jobs while applications are still online.
Start the migration jobs as soon as the server offline notification is received from the system
administrator.
•
To get optimum MPX200 performance, schedule a maximum of eight jobs to run simultaneously.
•
To sequentially run migration jobs, use the Serial Scheduling feature, which allows the migration
jobs to start automatically after the jobs with previous priority values are completed; no user
intervention is required. Serial scheduling helps ensure optimum bandwidth usage without
filling up array I/O queues, which may occur if jobs run simultaneously. Serial scheduling
works best when migrating multiple jobs of similar size.
•
Use the array bandwidth feature when applications are still using different LUNs of the array
while DMS is migrating the data. This ensures that the MPX200 uses limited array bandwidth
for the data migration and does not impact application performance during data migration.
General precautions
During any data migration, do not present the destination LUN to any host before the migration job is complete. To
cross-validate and verify at the host that the data has been copied correctly, ensure that the destination LUN is presented
to the host only after the verify job is completed at the router.
During offline data migration, ensure that hosts connected to source and destination LUNs are either zoned out
completely, or that LUN masking is changed appropriately such that the LUNs being migrated are not accessible by
any host other than the MPX200 until the migration is complete.
During offline data migration, ensure that the source LUN is not accessible to any host. Make the source LUN available
only to the router.
Before running an offline data migration job, ensure that the host is shut down.
During online data migration, the host I/Os are routed through the router paths. For HP-UX hosts, ensure that the
initiator type is set to HP-UX. In HP mpx Manager, in the left pane under the Discovered FC Initiators node, select an
initiator, and then in the Information window in the right pane, click HPUX in the OS Type Selection box. Or, in the
CLI, issue the initiator mod command, select the initiator, and then select the OS Type of HP-UX.
During online data migration, make the source LUN available to the host only through the router paths. Before
acknowledging online migration jobs, ensure that the host is shut down and remove the LUN mapping through the
router.
In HA configurations where the LUNs are visible from both MPX200 ports, ensure that both ports from each MPX200
blade are configured under a single host or host group entity of the type Windows/Windows 2003 in the array
management software. This configuration ensures that all MPX200 ports from the same VP group see the same set of
LUNs as having the same LUN ID. Failing to follow this configuration can lead to unpredictable or erroneous behavior.
For a dual-blade configuration for the MPX200, add the same VP group WWPNs from both blades as one host entry.
If you need to migrate more than 255 LUNs, you may create additional host entries in the array using WWPNs from
additional VP groups in the MPX200.
Migration logs require the following handling:
• Always clear migration logs at the start of the project.
•
Export migration logs onto your system after the project completes.
•
Migration logs wrap after 6,144 migration log entries.
If the source array controllers are configured in redundant fabrics, configure one MPX200 port into Fabric A and the
second port into Fabric B.
When using the serial scheduling feature, configure similar size jobs with the same priority.
142 Performance and best practices