Using HP PRM with Oracle Databases

4
Features
The following features should be understood before Oracle can be successfully integrated with PRM.
These features are described in detail in the sections that follow.
• PRM groups. PRM enables you to separate processes into Fair Share Scheduler (FSS) PRM groups
and into PRM groups based on pSets. With FSS PRM groups, the FSS allocates CPU resources to
certain processes. In addition, PRM can create pSets, with the processes getting CPU resources
allocated based on the number of CPUs, or cores, in the pSet. (A core is the actual data processing
engine within a processor. A single processor might have multiple cores. Starting with
HP-UX 11i v3, a core can support multiple execution threads. This feature is known as
Hyper-Threading. With Hyper-Threading disabled or unavailable, each core is seen as a CPU.
With Hyper-Threading enabled, each core can be seen as multiple, logical CPUs.)
• Oracle Database Resource Manager. Introduced in Oracle 8i, the Database Resource Manager is
an optional feature that can be successfully used with PRM C.02.00 or later when PRM is
configured appropriately.
• MRGs. The MRG feature introduced with PRM C.02.00 on HP UX 11i plays an important role in
isolating an Oracle database instance. When used in conjunction with pSet PRM groups, both
private memory and CPU resources can be isolated for a specific Oracle database instance.
PRM C.03.01 on HP-UX 11i v2 Update 2 or later introduced MRGs that can isolate shared
memory, which is useful for an Oracle database’s System Global Area (SGA).
• Secure Resource Partitions. HP-UX 11i v2 (B.11.23) offers the Security Containment feature. This
feature provides file and process isolation in secure compartments. Combining Security
Containment and PRM, you can form Secure Resource Partitions in which PRM controls resource
allocation for your secure compartments. Placing Oracle database instances in their own Secure
Resource Partitions enables you to provide another level of isolation to the instances.
• Application support. PRM application support provides the ability to place processes in specific
PRM groups.
FSS PRM groups
Each FSS PRM group is assigned a user-specified number of shares of the CPU resource pool. The
CPU resource pool consists of all the cores not assigned to a pSet. It is dedicated to the FSS PRM
groups. The shares value of a FSS PRM group is translated internally to a percentage of total system
CPU cycles. However, that percentage changes as other FSS PRM groups are added or deleted
because the shares ratio (group shares/total shares) changes. All FSS PRM groups must be associated
with, and share the resources of, the CPU resource pool. Although the CPU resource pool initially
consists of all the cores from the system, that number decreases as cores are assigned to pSet PRM
groups.
pSet PRM groups
Defining a pSet PRM group creates a pSet on the system. The pSet PRM group enables users and
applications assigned to this group to run within this pSet. You can associate only one pSet PRM
group with each pSet.
To illustrate how PRM works with pSets, consider an eight-core system with four cores assigned to a
pSet PRM group. The pSet PRM group has a hard limit of 50% of the system CPU resources. Other
FSS PRM groups can still be created, but their shares allocations now come from the remaining
unassigned cores in the CPU resource pool.
The PRM pSets feature is supported on HP-UX 11i running PRM C.02.00 or later.