Kernel-Managed Swap Facility (KMSF) Manual

Configuring KMSF

Kernel-Managed Swap Facility (KMSF) Manual—425824-005

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Location of KMSF Swap Files

Listed below are general guidelines for locations to place KMSF swap files:

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Default swap files are located on $SYSTEM, which has a high activity rate and is

often near capacity. Putting configured swap files on a different mirrored volume

can improve system performance.

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Place swap files on volumes that do not have high activity for data other than the

swap files themselves. Otherwise, your system performance might be affected.

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Place your swap files on mirrored disks. See Avoiding Processor Halts on

page 2-1.

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Balance the load of all disk I/O across disk volumes.

Naming Configured Swap Files

When you name configured swap files, avoid using the naming scheme for default

swap files, $SYSTEM.ZSYSSWAP.SWAPnn, where nn represents the number of the

processor. If you use a name for a configured swap file that matches the names for

default swap files, the results are unpredictable.

Because you might have multiple configured swap files dedicated to a processor,

choose a naming scheme that allows you to easily identify both the processor number

and the swap file. In this manual, examples for configured swap files use the naming

convention CPUnna, where nn is the processor number and a is a letter representing

the swap file. For example, the set of configured swap files for processor 1 might

include CPU01A, CPU01B, and CPU01C.

Amount of Swap Space to Allocate

Determining the amount of swap space to allocate depends greatly on your system

usage and workflow patterns. You can dynamically adjust the number and size of swap

files as needed, using NSKCOM (see Section 3, Managing KMS Files).

Initial Allocation

These recommendations are a starting point. To determine how to adjust the swap

files as appropriate for your system, see Configuration Guidelines on page 2-3.

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For systems running G-series RVUs: Initially, allocate swap space for each

processor equaling twice the physical memory of the processor. For example, if the

processor has 256 megabytes of physical memory, allocate 512 megabytes for the

processor’s swap files.

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For systems running H-series RVUs: Initially, allocate swap space for each

processor equalling four times the physical memory of the processor. For example,

if the processor has 16 gigabytes of physical memory, allocate 64 gigabytes for the

processor’s swap files.