Before you begin: To understand how to use IGDSMSxx parameters, see z/OS MVS Initialization and Tuning Reference. For more information about the buffer management statistics recorded in the SMF type 42 record, see the z/OS MVS System Management Facilities (SMF).

Perform the following steps to plan for using the restartable PDSE address space feature:

1. Decide whether to IPL z/OS using just the SMSPDSE address space or both the SMSPDSE and SMSPDSE1 address spaces, depending on your processing environment.

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2. Determine the appropriate settings for the following IGDSMSxx parameters:

   PDSE_RESTARTABLE_AS(YES|NO)

   The default is NO which means that the restartable PDSE address space, SMSPDSE1 is not created at initialization. If you specify YES, the SMSPDSE1 address space is created at initialization.

   PDSE1_MONITOR ({YES|NO}[,interval[,duration]])

   The default is YES which turns on PDSE1 monitor processing. If you specify NO, monitor processing is turned off. If you omit this parameter, the monitor is started with a default value of 60 seconds for interval processing and 15 seconds for duration processing. The interval is the number of seconds between successive scans of the monitor. The duration is the number of seconds a possible error condition must exist before it is treated as an error.

   PDSE1_LRUCYCLES(nnn|240)

   The default is 240 cycles. This parameter specifies the number of times (5 to 240 cycles) that the buffer management facility (BMF) least-recently-used (LRU) routine passes over inactive buffers before making them available for reuse. Most installations should use the default value. For very high data rates, you might change this value to improve performance.

   PDSE1_LRUTIME(nnn|15)

   The default is 15 seconds. This parameter specifies the number of seconds (5 to 60) that the BMF waits before calling the BMF LRU cache. Most installations should use the default value. For very high data rates, you might change this value to improve performance.

   PDSE1_HSP_SIZE(nnn)

   The default is either 256 MB of expanded storage or half of the system's available expanded storage, whichever amount is lower. You can request up to 512 MB for the SMSPDSE1 hiperspace storage. You also can indicate that the hiperspace is not to be created by setting PDSE1_HSP_SIZE to 0. This parameter has no effect if you specify RESTARTABLE_PDSE_AS(NO) or allow it to default.

   PDSE1_BMFTIME(nnn|3600)

   The default is 3600 seconds (one hour). This parameter specifies that SMS is to wait between recording SMF records for BMF cache use for the SMSPDSE1 address space. You can specify a value of 1 to 86 399 (23 hours, 59 minutes, 59 seconds). The SMF_TIME keyword, if set to YES, overrides the PDSE1_BMFTIME keyword.

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Now you are ready to set up the SMSPDSE1 address space.