The Partition Load Manager (PLM) provides CPU and memory resource management and monitoring across logical partitions (LPARs). Partition Load Manager allows you to effectively use CPU and Memory resources by allowing you to set thresholds for designated resources. When a threshold is exceeded, Partition Load Manager can try to assign CPU and/or Memory resources to that LPAR by using resources assigned to other LPARs that are not being used.
Determining which node is more or less deserving of resources is primarily done by taking into account certain values defined in what is known as a policy file. This policy file details partitions, their entitlements, their thresholds, and organizes the partitions into groups. Every node, but not every LPAR, managed by Partition Load Manager must be defined in the policy file along with several associated attribute values. Some of the attributes that are associated with the node are the maximum, minimum, and guaranteed resource values, variable share values, and so on. These are the attributes taken into consideration by Partition Load Manager when a decision is made as to whether a resource is reallocated from one LPAR to another.
PLM is an automated mechanism for utilizing the Dynamic LPAR (DLPAR) capabilities of the HMC and requires communication with the HMC. This means that before PLM will function, DLPAR must be functional on the HMC. DLPAR requires communication with each LPAR via the Resource Monitoring and Control (RMC) subsystem.
NOTE: The RMC subsystem is not installed when the AIX operating system is installed from the NIM server as an "rte" install.
The following fileset must be installed on every PLM client LPAR to enable RMC communications with the HMC and PLM:
The PLM communications are also dependent upon SSH and SSL and must be installed on every PLM client LPAR.
Refer to the PLM configuration procedures for more information
A single PLM server can manage multiple frames across multiple HMC's. In the Mt Xia environment there is a single primary PLM in each data center. Within a frame there are two classifications of CPU's, dedicated and shared. Policy files are used by the PLM to control each frame and a single policy file will exist for each frame. The policy file is named for the serial number of each frame. When new frames are added to Mt Xia's environment, a policy file will be created on the PLM and the name of the policy file will be the serial number of the frame. Policy files currently exist with names such as:
Every LPAR created in the Mt Xia environment will be managed by a PLM and will be initially assigned a minimum amount of CPU and memory resources. This means there will be a policy file on the PLM for every frame in the data center where the PLM exists.
Within a PLM policy there are two groups to represent the two CPU classifications, dedicated and shared. Each LPAR will be assigned to one of these two groups, depending upon what type of CPU's are assigned to the LPAR.
As a configuration standard, every policy will be configured to immediately release free CPU and memory resources. Most other configuration parameters within the PLM will depend upon the LPAR and application requirements.