Advanced POWER Virtualization on IBM System p5 - Previous ...

I/O configuration, performance is an important aspect that should be given
careful consideration.
Virtual SCSI runs at low priority interrupt levels, while virtual Ethernet runs on
high priority interrupts due to the latency differences between disks and LAN
adapters. A client that produces extensive network activity has the potential to
impact performance of a client that requires extensive disk activity as the virtual
Ethernet has higher priority interrupts. Either a larger Virtual I/O Server with
more CPU resources will be required or a second Virtual I/O Server can be
considered to split the two high throughput clients.
2.10 Partition Load Manager introduction
The Partition Load Manager (PLM) software is part of the <strong>Advanced</strong> <strong>POWER</strong>
<strong>Virtualization</strong> feature and helps clients maximize the utilization of processor and
memory resources of dynamic LPAR-capable logical partitions running AIX 5L.
The Partition Load Manager is a resource manager that assigns and moves
resources based on defined policies and utilization of the resources. PLM
manages memory, both dedicated processors, and partitions using
Micro-Partitioning technology to readjust the resources. This adds additional
flexibility on top of the micro-partitions flexibility added by the <strong>POWER</strong>
Hypervisor.
PLM, however, has no knowledge about the importance of a workload running in
the partitions and cannot readjust priority based on the changes of types of
workloads. PLM does not manage Linux and i5/OS partitions.
Partition Load Manager is set up in a partition or on another system running AIX
5L Version 5.2 ML4 or AIX 5L Version 5.3. Linux or i5OS support for PLM and the
clients is not available. You can have other installed applications on the partition
or system running the Partition Load Manager as well. A single instance of the
Partition Load Manager can only manage a single server.
Partition Load Manager uses a client/server model to report and manage
resource utilization. The clients (managed partitions) notify the PLM server when
resources are either under- or over-utilized. Upon notification of one of these
events, the PLM server makes resource allocation decisions based on a policy
file defined by the administrator.
Figure 2-25 on page 103 shows an overview of the components of Partition Load
Manager. In this figure, the PLM server would be notified by the database
partition that it requires additional processor resources. The Web server partition
would also have notified the PLM server that it has an abundance of processor
102 <strong>Advanced</strong> <strong>POWER</strong> <strong>Virtualization</strong> on IBM System p5