Live Partition Mobility requirements

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Live Partition Mobility requirements

The requirements for successful migration of active LPARs between Power Systems servers using PowerVM Live Partition Mobility include the following:

Both source and target server must have POWER6 CPUs and both must have PowerVM Enterprise Edition installed. JS22 blades are eligible (but not JS21)

If HMC-managed, both servers must be managed by the same HMC until Release 7 Version 3.4 of the HMC code, which introduced the ability to migrate between different HMCs. If IVM-managed, neither server can be HMC-managed. Integrated Virtualization Manager (IVM) is a component of PowerVM. (Thanks to VinceJohnson for his comment on 9/24/2010 suggesting improvements to this paragraph.)

LPAR to be moved must be running AIX V5.3, AIX V6.1, or Linux

Virtual I/O servers on the two servers must be able to communicate over the network

In the move preparation phase, the contents of an LPAR's memory must be transmitted over virtual Ethernet (via Virtual I/O Servers) from the source LPAR to the target LPAR. Pages updated after transmission must be transmitted again. Assuming a Gigabit Ethernet can transmit 80 MB/sec and that 256 GB of working memory is in use on the source LPAR, it will take at least 256*1024/80 = 3276.8 seconds or one hour to prepare for the move if only a gigabit of network bandwidth is available. That's assuming source working memory pages are not updated after they are transmitted, which is NOT a good assumption, so actual time will be longer. The Virtual I/O Servers will consume roughly one CPU on the source and one on the target managing the data transmission. (See VIOS Sizing for more information on estimating CPU consumption by a VIO Server.) And unless sufficient network bandwidth is available to accommodate the additional network activity, application network bandwidth and response time will be impacted during the move preparation phase.

Once the move preparation phase is complete, only a few seconds are required to actually move the LPAR.

All I/O must be virtualized in an LPAR to be moved - any dedicated PCI adapters must be deallocated before the LPAR can be moved

AIX must boot from LUNs accessible to both virtual I/O servers. Considerations when booting from SAN suggest that AIX dump space be configured on a SCSI hdisk dedicated to the LPAR or on a vSCSI disk which is mapped to an internal SCSI disk dedicated to a virtual I/O server LPAR. AIX dump space must therefore be deallocated (or perhaps reallocated to a LUN) prior to moving the LPAR and (re)allocated to a (different) dedicated SCSI disk after moving the LPAR.

Network switches and routers must support and properly handle gratuitous ARP packets, so that when the network sees the LPAR's IP (and MAC?) addresses jump from one network port to another, the jump will be handled properly.