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How Many Buffer Pools are Needed Z o/s:

How Many Buffer Pools are Needed Z o/s:

· Restrict BP0 for Catalog and Other System Page sets

PGFIX Recommended

· Sort and Work data sets (1 pool): usually BP7

PGFIX = YES

VPSEQT = 99 (IF solely used for Sort and Work data operations)

PGSTEAL = LRU

PGSTEAL! = FIFO (since sort merge operations would be severely impacted)

· 1 or more pools for “data in memory “Table space AND Index space.

PGFIX = YES (IF I/O’s occur OR to prevent the paging of the pool under any circumstance due to high priority and small size)

PGFIX= NO (IF you do over sizing of the pool AND if all objects in the pool are primarily read only).

VPSEQT=0 (prevents the scheduling of a prefetch engine for the data that is already in the pool)

VPSEQT=100 (If you wish to prime the pool by selecting the whole table)

Set VPSEQT = 100 before the prime process and reset VPSEQT = 0 afterwards).

PGSTEAL = FIFO (If the read I/O rate is zero or minimal)

4KB pools for USER data

Separate Table spaces AND index spaces

Table space < Index space (As Table space is expected to have more asynchronous I/O than Index space)

Table Space pool’s VPSEQT > Index Space pool’s VPSEQT

40%-80% 20%-40%

· If System Residency Time = Random Page Residency Time= Sequential Residency Time for most of the periods, then LOWER VPSEQT until the Threshold becomes effective.

· Separate pools for LOB Table Spaces (due to different nature of GETPAGE and I/O activity)

· Separate pools have to be used to prioritize one set of objects over other

· It is necessary to separate out some objects due to special performance requirements and need to monitor access to the objects closely.

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How Many Buffer Pools are Needed Z o/s:

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