What’s new in Live Partition Mobility?
In September 2021, with the introduction of the new E1080 server, IBM made some changes and enhancements to our Live Partition Mobility support (LPM). LPM is used by many customers both on-premises and in cloud environments to move a running logical partition (LPAR) from one POWER server to another without any downtime. This migration can span different generations of POWER servers, for example moving an LPAR running on POWER8 to Power10. The following sections provide more information on these changes.
LPM from previous generations of POWER systems
Power10 supports migration from POWER8 (when running in Power8 compatibility mode or default mode if running in POWER8 mode), POWER9 (Power9_base, Power9 or default mode if running in POWER8 or POWER9 mode) or from another Power10 server. IBM’s goal for LPM is to support N-2 hardware generations.
In previous versions of PowerVM, if an optical device was assigned to a logical partition, the customer needed to remove the device from the partition. Starting with VIOS 3.1.3 if there is no media loaded in the optical device, the LPM operation will be allowed, and a new optical device will be created for the partition on the destination server. These changes are specific to VIOS 3.1.3 so you can benefit from this LPM improvement even on earlier generations of POWER servers.
Automatic selection of network device in Mover/Server partition
In previous versions when an LPM operation was performed and the request did not explicitly specify a network device that should be used by the Mover/Server partition, PowerVM would just select a device that could transmit the data. With the latest version of PowerVM, the device selection is based on the performance characteristics of the device. For example, if there is a 1Gb network adapter and a 10Gb network adapter that could be used to perform the migration, the 10Gb network would be the first choice to be used for the migration. If you had two different 10Gb network adapters, concurrent migration requests would be split evenly across the adapters. If you have a 10Gb dedicated connection in the MSP and a 10Gb Shared Ethernet Adapter (SEA), the dedicated connection would be chosen over the SEA connection. If you want to explicitly select the connection to be used instead of allowing the firmware to automatically chose the connection, this can be specified on the migrlpar HMC CLI command.
These changes are specific to HMC version 10 so you can benefit from this LPM improvement even on early generations of POWER servers.
Migration between Power10 and previous POWER server
IBM is recommending that you install service pack FW1010.10 (MH1010_094) on your Power10 server if you are going to be performing migrations operations from POWER8 or POWER9 to Power10. Without service pack FW1010.10, there are documented restrictions when migrating from some previous versions to Power10. The Fix Level Recommendation Tool (FLRT) with Live Partition Mobility Recommendations documents these known issues and restrictions.
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