AIX support for POWER7
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By now you will have heard about the exciting next
generation of Power Systems servers based on the POWER7 processors.
This is the first time that IBM has launched a new
generation of UNIX hardware without requiring a new Technology Level of AIX or
worse yet, a new AIX version. This is an outcome of the release and service
strategy changes that we made to AIX back in 2007 based on client feedback. (for
more info see http
We also plan to support the new POWER7 based systems on AIX 6 TL2 & TL3 and AIX 5.3 TL9 & TL10, but those service packs with that support will come later in the year.
This capability is largely made possible by a capability of the POWER7 processors to run in three modes: POWER7, POWER6+ and POWER6 mode. Each LPAR running on a POWER7 based system can run in one of these modes. Different LPARs on the same system can run in different modes. This mode setting is controlled by the partition definition when the LPAR is created on the hardware management console (HMC).
This POWER7 processor capability allows the clients to relocate LPARs with Live Partition Mobility (a feature of PowerVM Enterprise Edition) to and from systems running on POWER6, POWER6+ and POWER7 processors.
For example, if you relocate a LPAR from a POWER6+ based system to a POWER7 based system, the LPAR, will be running on POWER6+ mode when it arrives at the destination system. The relocated LPAR will continue to run in POWER6+ mode unless the administrator changes the partition definition using the HMC and reboots the LPAR. This capability provides an easy way for clients to move up to POWER7 based systems without experiencing an outage.
You can also create partitions on a POWER7 system that are running in POWER6 or POWER6+ mode. You would do this if you wanted to provide the capability to relocate the partition to a POWER6 or POWER6+ based system, or if you were running AIX 5.3 or older Technology Levels of AIX 6 (TL2 or TL3).
AIX 6 at Technology Level 4 or later can run in any of these three modes but AIX 5.3 will only run in POWER6 or POWER6+ modes.
So what is the effect of running in a POWER6 or POWER6+ mode versus POWER7 mode? Well, if the LPAR is not running in the POWER7 mode, AIX and the applications running in that LPAR would not be able to run in 4 thread Simultaneous MultiThreading (SMT) mode, and would not have access to the new double precision Vector Scalar Extension (VSX) instructions or the additional memory protection keys supplied by POWER7 processors.
For many applications, the flexibility of being able to relocate LPARs between POWER6 and POWER7 based systems will outweigh the downside of not running in POWER7 mode, but clients will be able to make this decision on a per LPAR basis. Please note that other features of the POWER7 processor based systems such as the advanced Energy management features will work in any of the three modes.
If you do want to change the mode of an LPAR (assuming that the level of AIX you are running supports the new mode), all you have to do is change the partition definition for the LPAR using the HMC and reboot the LPAR.
Hopefully this information has given you some insight into one of the exciting new capabilities provided by POWER7 processor based systems and how AIX is leveraging these new capabilities.