Quickly and easily allocate system resources across multiple logical partitions 
Add resources such as newly activated CUoD processors without re-booting the server 
The new dynamic logical partitioning (dynamic LPAR) function provides enhanced resource management for the pSeries 670 and 690 servers. Dynamic LPAR allows available system resources to be quickly and easily configured across multiple logical partitions to meet the rapidly changing needs of your business. Dynamic LPAR also allows you to add new system resources such as newly activated CUoD processors or new hot plug PCI adapters into your system's configuration without requiring a re-boot. 

AIX 5L for V5.2 or later 
Hardware Management Console for pSeries with V1.3 or later software 

p670/p690 (7040-671 or 7040-681) system microcode (machine code) at the October 2002 update or later 

--------------------------

Question: What is required to enable dynamic capable LPARs?

Answer: An upgrade of AIX, HMC, and Platform Firmware is required. The required levels are as follows:

AIX: 5.2
HMC: Release 3, Version 1.0
Platform Firmware: 10/2002 system firmware or later.

To determine platform firmware level, on any AIX partition type:
lscfg -vp | grep -p Platform.
The last 6 digits of the ROM Level represent the Platform Firmware date in the format: "YYMMDD".

Question: How much time does it take for a DLPAR operation to complete?

Answer: In general, on a non-loaded system, a single processor move can take less than a minute. Memory moves may take a few more minutes than a processor move.
 

Question: How is the "detail level" option in the HMC used?

Answer: This sets the various level of debug output displayed during DLPAR operations. Additionally, this allows the user to see all the steps that AIX performed in the DLPAR operation providing tracing/logging information for debug and problem determination.
 

Question: How is the timeout value for DLPAR operations used by the HMC?

Answer: The user can set a time limit (in minutes) setting so that the DLPAR operation request will be canceled if the pre-set time limit is exceeded. An example is a situation requiring memory moves. When the memory cannot be re-allocated because resource memory is pinned to the physical memory, sometimes certain operations will take a very long time to complete. A time limit in this case may be used to limit the amount of retries that take place. A time limit of zero implies that there is no time limit.
 

Question: With a timeout limit of zero, how can I stop a command that may not complete because the DLPAR command will not succeed?

Answer: Although a user may set the timeout limit to zero, HMC and AIX each have a set of default behaviors that will ensure a DLPAR command, that will eventually fail, will return with the appropriate error message.
 

Question: If we do dynamic configuration, what will happen to the process pinned or accessing direct memory?

Answer: Nothing. If a process has pinned memory, the virtual memory manager transparently migrates the data to a new pinned physical page and atomically updates the virtual to real page mappings to point to the new physical page.
 

Question: Are there special AIX filesets or PTF levels required for DLPAR?

Answer: The installation of AIX 5.2 is adequate for current pSeries LPARs to perform dynamic operations.
 

Question: Are applications affected by DLPAR operations?

Answer: A large majority of applications should be DLPAR unaware, which means they are not programmed to take advantage of DLPAR capabilities from within the application. Thus, they should not be affected by DLPAR. Only programs considered "DLPAR aware" might be affected by DLPAR actions.
 

Question: What is a "DLPAR aware" application?

Answer: A DLPAR aware application cares about the resource levels allocated to the partition and can alter its behavior based on changes in the resource levels. AIX provides APIs for applications that wish to be DLPAR aware.
 

Question: What is the relationship between DLPAR and Capacity Upgrade on Demand (CUoD)?

Answer: DLPAR can be used to bring online a resource that has been activated through CUoD.
 

Question: How does Dynamic Processor Deallocation work with Dynamic Processor Sparing?

Answer: If spare (unlicensed CUoD) processors are available, the partition should be able to assign and bring online these processors before it deactivates a failing processor.
 

Question: How does affinity partitioning relate to DLPAR?

Answer: Users can perform DLPAR operations on I/O slots with affinity partitions, but not with processor or memory resources.
 

Question: Are there any examples of using the HMC command line to automate DLPAR?

Answer: The DLPAR toolset avaliable on alphaworks provides tools that automate DLPAR operations using the HMC command line.