Using cabinet copies

Cabinet copies provide a performance enhancement when you are copying a large number of spaces. In such cases, the overhead to open and close each copy data set can be a significant component of overall run time.

Cabinet copies allow you to copy all the spaces in a group into a single data set called a cabinet file. The cabinet file is allocated and deallocated only once, regardless of the number of objects that are copied to or recovered from the cabinet file. Because there is no file opening or closing for each space in the cabinet file, the file header and trailer records, including the EOF markers, are omitted from cabinet files, and performance is greatly improved. You can copy the cabinet files to either DASD or tape.

In addition to providing a performance enhancement, cabinet copies can save resources because using cabinet copies can

• Save disk space because of the efficient use of space within a cabinet file
• Reduce the number of MVS catalog entries

BMC AMI Recover automatically detects and uses cabinet copies if they are available for recovery for any spaces in the cabinet copy. Phases to recover objects will be planned in the order that the object image copies appear in the cabinet copy unless this would conflict with other planning restrictions such as change accumulation files or output copies.

Restrictions for cabinet copies

The following restrictions apply to cabinet copies:

• A minimum z/OS level of 1.7 is required for cabinet copies made to disk.
• For a recovery using cabinet copies, you must use BMC AMI Recover version 8.1.00 or later.
• An image copy contained within a cabinet copy must have a row present in BMCXCOPY on the subsystem on which the recovery is run.

• The INCOPY option of BMC AMI Recover does not support cabinet copies.

  Important

  If you have only a cabinet copy and need to do a drop recovery, you can use the BMC AMI Copy COPY IMAGECOPY command to unstack a cabinet copy and register the copies in SYSCOPY. You can then use the individual copies with the INCOPY option.

• Online consistent copies, another feature of the Recovery Management for Db2 solution, do not support cabinet copies.
• You cannot make cabinet copies using the Instant Snapshot functionality.

Registration of cabinet copies

Because cabinet copies can be recovered only by using BMC AMI Recover, they are registered in the BMCXCOPY table. A COPY_TYPE value of C indicates the copy is a cabinet copy. A row is created for each member within the cabinet copy and each member has the same DSNAME. The DSNAME is the name of the cataloged cabinet file as indicated in the BMC AMI Copy OUTPUT command. The cabinet members are individually registered in BMCXCOPY as uncataloged. The cabinet file is always cataloged.