Edit: vSCSI or NPIV both work for LPM
Originally posted December 3, 2019 on AIXchange
Moving to POWER9? Live Partition Mobility (LPM) can be used to virtualize storage on LPARs connected to VIO servers via vSCSI.
Recently I was asked if it’s possible to perform Live Partition Mobility (LPM) operations on LPARs that are connected to VIO servers via vSCSI. Since N_Port ID virtualization (NPIV) is so common now, I actually had to think about it, but the answer is yes, you can virtualize your storage either way. In fact originally, LPM was delivered and worked exclusively with vSCSI.
This means that shops that are preparing for the arrival of new POWER9 hardware should be able to migrate with no downtime, assuming their older systems are virtualized and that the SAN is zoned properly. Below is an excerpt from the IBM Developer page on LPM:
“You must have a minimum of two machines, a source and a destination, on POWER6 or higher with the Advanced Power Virtualization Feature enabled. The operating system and application must reside on a shared external storage (Storage Area Network). In addition to these hardware requirements, you must have:
- One hardware management console (optional) or IVM.
- Target system must have sufficient resources, like CPU and memory.
- LPAR should not have physical adapters.
Your virtual I/O servers (VIOS) must have a Shared Ethernet Adapter (SEA) configured to bridge to the same Ethernet network which the mobile partition uses. It must be capable of providing virtual access to all the disk resources which the mobile partition uses (NPIV or vSCSI). If you are using vSCSI, then the virtual target devices must be physical disks (not logical volumes).”
Also note the limitations of LPM, as Jaqui Lynch explains (excerpted below):
“LPM is not a replacement for disaster recovery or high availability solutions. It’s designed to move a running LPAR or a properly shutdown LPAR to a different server. It cannot move an LPAR with a crashed kernel or from a failed machine. If all the prerequisites are met, LPM can be used to move an AIX, IBM i or Linux LPAR from one LPM-capable POWER server to another compatible server. By compatible I mean that it has to meet the requirements for the Power Systems server, the management console, the VIOS (PowerVM) and the LPAR itself.”
Finally, this reminder. When you purchase POWER9:
“Each system will have PowerVM Enterprise Edition built in, and IBM is helping customers migrate by providing 60-day temporary licenses for existing machines that don’t already have PowerVM Enterprise Edition. This will allow you to use live partition mobility to migrate running workloads from existing POWER7 or POWER8 machines to your new POWER9 machine.”