Tuning Performance › VSAM Data Set Tuning › Buffer Sharing

Buffer Sharing

Buffer sharing is controlled by the VSAM LSR (Local Shared Resources) facility. By sharing buffers, data set I/O is reduced. The shared buffers are defined in LSR in pools.

To enable buffer sharing for a VSAM data set, use the UDBCTL OPEN command with the LSR operand.

Note: For files allocated through Customizer parameter groups, you can enter UDBCTL operands as VSAM options. For more information about the UDBCTL command, see the online help.

When specifying the LSR pool definition that best suits your needs, consider the following factors:

• Your need for virtual storage versus I/O performance
• The mix of VSAM files that you have open concurrently in the address space and which of those you want to place in the LSR pool

To define your LSR pool definitions, use the LSRPOOL parameter group (enter /PARMS).

Note: VSAM alerts warn about string or buffer shortages.