Use CSQ6LOGP

Use this topic as a reference for how to specify logging options using CSQ6LOGP.

Use CSQ6LOGP to establish your logging options.

COMPLOG

Specifies whether log compression is enabled. Specify either:

NONE

Log compression is not enabled.

RLE

Log compression is enabled using run-length encoding.

ANY

The queue manager selects the compression algorithm that gives the greatest degree of log record compression. This option results in RLE compression.

The default is NONE.

For more details about log compression, see Log compression.

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

Specify 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 IBM 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 Manage IBM MQ resources.

MAXCNOFF

Specifies the number of CSQJOFF7 offload tasks that can be run in parallel.

This allows a queue manager, or queue managers, to be tuned such that they will not use all the available tape units.

Instead the queue manager waits until a CSQJOFF7 offload task has completed before trying to allocate any new archive data sets.

If the queue manager is archiving to tape, set this parameter so that the number of concurrent tape requests should not equal, or exceed, the number of tape units available, otherwise the system might hang.

Note that if dual archiving is in use, then each offload task performs both archives, so the parameter needs to be set accordingly. For example if the queue manager is dual archiving to tape, a value of MAXCNOFF=2 would allow up to two active logs to be archived concurrently to four tapes.

If several queue managers are sharing the tape units, we should set the MAXCNOFF for each queue manager accordingly.

The default value is 31.

Specify a value in the range 1 through 31.

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 IBM 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 IBM MQ. If you do otherwise, the offload process could be delayed, which could affect the performance of our 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 offload 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 we 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 IBM 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 128 through 4000. The value specified is rounded up to a multiple of 4. Values between 40 and 128 will be accepted for compatibility reasons, and are treated as a value of 128.

The default is 4000 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, see Manage IBM MQ resources.

TWOARCH

Specifies the number of archive logs that IBM MQ produces when the active log is offloaded. 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, see Manage IBM MQ resources.

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, see Manage IBM MQ resources.

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 IBM 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.

ZHYWRITE

Specifies whether writes to the active logs are made with zHyperWrite being enabled. The active log datasets need to be on zHyperWrite capable volumes for zHyperWrite to be enabled.

For more information on enabling active logs with zHyperWrite, see Use zHyperWrite with IBM MQ active logs.

The value can be:

NO

zHyperWrite is not enabled.

YES

zHyperWrite is enabled.

Parent topic: Tailor the system parameter module

Related reference

• Use CSQ6SYSP
• Use CSQ6ARVP