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DISK_SYSPARM_IOCHNBLK_1

Description

Setting the sysparm IOCHNBLK to the value 1 or allowing it to use the default value 1, causes Backup and Archive jobs to write only one block to a tape at a time. This causes the job to run slower and to use more processing time. Sysparm IOCHNBLK can accept a value from 1 to 9, which is the number of tape blocks to be written with one I/O. Setting a value of 9 generally improves the performance significantly. This exception will be cleared when this check runs again after the job causing the exception is changed and runs, or after the job statistics are older than the number of days specified in the AGE parameter for this health check. The default for the sysparm IOCHNBLK will be changed to 9 with the next release of CA Disk.

Best Practice

Set the sysparm IOCHNBLK to 9 to get the best performance on tape I/O activity during a Backup or Archive job. Getting the best performance on tape I/O results in reduced processing time for your required Backup and Archive jobs, which will shrink the Backup/Archive processing window.

Parameters Accepted

AGE(7)

Debug Support

Yes

Verbose Support

Yes

Reference

For more information, see the Systems Guide.

Messages

ADSH002IE Sysparm IOCHNBLK is set to 1 while using a tape device.