Using CSQ6LOGP

Use CSQ6LOGP to establish your logging options.

The default parameters for CSQ6LOGP, and whether we can alter each parameter using the SET LOG command, are shown in Table 9. If we need to change any of these values, refer to the detailed descriptions of the parameters.

Table 9. Default values of CSQ6LOGP parameters
Parameter Description Default value SET command
DEALLCT Length of time an archive tape unit remains unused before it is deallocated. zero X
INBUFF Size of input buffer storage for active and archive log data sets. 60 KB -
MAXARCH Maximum number of archive log volumes that can be recorded. 500 X
MAXRTU Maximum number of dedicated tape units allocated to read archive log tape volumes concurrently. 2 X
OFFLOAD Archiving on or off. YES (ON) -
OUTBUFF Size of output buffer storage for active and archive log data sets. 4 000 KB -
TWOACTV Single or dual active logging. YES (dual) -
TWOARCH Single or dual archive logging. YES (dual) -
TWOBSDS Single or dual BSDS. YES (dual BSDS) -
WRTHRSH Number of output buffers to be filled before they are written to the active log data sets. 20 X

DEALLCT

Specifies the length of time, in minutes, that an archive read tape unit is allowed to remain unused before it is deallocated.

Specify one of the following:

  • Time, in minutes, in the range zero through 1440

  • NOLIMIT

Specifying 1440 or NOLIMIT means that the tape unit is never deallocated.

The default is zero.

When archive log data is being read from tape, it is recommended that you set this value high enough to allow WebSphere MQ to optimize tape handling for multiple read applications.

INBUFF

Specifies the size, in kilobytes, of the input buffer for reading the active and archive logs during recovery. Use a decimal number in the range 28 through 60. The value specified is rounded up to a multiple of 4.

The default is 60 KB.

Suggested settings:

Test system 28 KB
Production system 60 KB

Set this to the maximum for best log read performance.

MAXARCH

Specifies the maximum number of archive log volumes that can be recorded in the BSDS. When this number is exceeded, recording begins again at the start of the BSDS.

Use a decimal number in the range 10 through 1000.

The default is 500.

Suggested settings:

Test system 500 (default)
Production system 1 000

Set this to the maximum so that the BSDS can record as many logs as possible.

For information about the logs and BSDS, see the WebSphere MQ for z/OS Concepts and Planning Guide.

MAXRTU

Specifies the maximum number of dedicated tape units that can be allocated to read archive log tape volumes concurrently.

This parameter and the DEALLCT parameter allow WebSphere MQ to optimize archive log reading from tape devices.

Specify a value in the range 1 through 99.

The default is 2.

It is recommended that you set the value to be at least one less than the number of tape units available to WebSphere MQ. If you do otherwise, the off-load process could be delayed, which could affect the performance of your system. For maximum throughput during archive log processing, specify the largest value possible for this option, remembering that we need at least one tape unit for off-load processing.

OFFLOAD

Specifies whether archiving is on or off.

Specify either:

YES

Archiving is on

NO

Archiving is off

The default is YES.

Attention:
Do not switch archiving off unless you are working in a test environment. If you do switch it off, we cannot guarantee that data will be recovered in the event of a system or transaction failure.

OUTBUFF

Specifies the total size, in kilobytes, of the storage to be used by WebSphere MQ for output buffers for writing the active and archive log data sets. Each output buffer is 4 KB.

The parameter must be in the range 40 through 4000. The value specified is rounded up to a multiple of 4.

The default is 4 000 KB.

Suggested settings:

Test system 400 KB
Production system 4 000 KB

Set this value to the maximum to avoid running out of log output buffers.

TWOACTV

Specifies single or dual active logging.

Specify either:

NO

Single active logs

YES

Dual active logs

The default is YES.

For more information about the use of single and dual logging, refer to the WebSphere MQ for z/OS Concepts and Planning Guide.

TWOARCH

Specifies the number of archive logs that WebSphere MQ produces when the active log is off-loaded.

Specify either:

NO

Single archive logs

YES

Dual archive logs

The default is YES.

Suggested settings:

Test system NO
Production system YES (default)

For more information about the use of single and dual logging, refer to the WebSphere MQ for z/OS Concepts and Planning Guide.

TWOBSDS

Specifies the number of bootstrap data sets.

Specify either:

NO

Single BSDS

YES

Dual BSDS

The default is YES.

For more information about the use of single and dual logging, refer to the WebSphere MQ for z/OS Concepts and Planning Guide.

WRTHRSH

Specifies the number of 4 KB output buffers to be filled before they are written to the active log data sets.

The larger the number of buffers, the less often the write takes place, and this improves the performance of WebSphere MQ. The buffers might be written before this number is reached if significant events, such as a commit point, occur.

Specify the number of buffers in the range 1 through 256.

The default is 20.