CA-L-Serv › Define Managed Files › Performance Adjustments

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Performance Adjustments

You can improve I/O performance for most CA-L-Serv managed files by changing any of the following OPTION parameter values on the ADDFILE command:

What You Can Do

OPTION Value

Considerations

Defer write operations for a record until the VSAM buffer is needed for another operation or the deferred write interval expires.

DEFER
  • Use DEFER only with LSR buffer pools.
  • Speeds updates, deletions, and insertions.
  • The deferred write interval is set through the MAXDORM parameter on the OPTIONS command.
  • The most recent version of a record may be lost if a system problem occurs before the data is physically written to a disk.

Pad short records with blanks until the records are nn bytes long.

MINLEN(nn)
  • MINLEN is a safeguard to the TRIM option because it ensures that clients receive records in the length they expect.
  • Do not specify MINLEN unless directed to do so by the client documentation.

Trim trailing blanks from the data portion of variable length records.

TRIM
  • Saves disk space by reducing the record length before the record is stored on disk.
  • Never affects the key portion of a record.
  • Do not use TRIM if the VSAM data set has been defined with fixed length records.

For example, to set performance options for the file DPMFSIF, specify the following command in the CA-L-Serv parameter data set:

ADDFILE DPMFSIF OPTION(TRIM,DEFER) POOL(3)

Important! Misuse of these options can cause serious I/O or other system problems. CA strongly recommends that you use the default values provided by the client application that uses the file.