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Space announcement This space now contains the documentation for all the following components:
  • CHANGE ACCUMULATION PLUS
  • IMAGE COPY PLUS
  • RECOVERY MANAGER for IMS
  • RECOVERY PLUS for IMS
We are no longer updating the individual documentation spaces for these components. For the latest documentation, see BMC AMI Backup and Recovery for IMS 5.2.

Asynchronous recoveries with change accumulation input

As described for logs in the previous paragraph, processing overlap can also be lost if a change accumulation file is input to one or more asynchronous recoveries.

To minimize this limitation, allocate as much storage for the change accumulation buffer pool as possible. For example, by using

Related topics

Planning-a-recovery-strategy-using-the-Recovery-utility


ACCUM ACCUM(*) NBUF(80)

you allocate 80 64 K buffers above the 16 MB line for a total pool size of 5 megabytes. This pool is used to contain the change accumulation records as they are selected for processing for a particular recovery task. Be sure to check with your system programmer to find out a reasonable upper limit to set for the size of this pool.

If, for example, you were trying to recover three database data sets and each data set contained 5,000 records on the change accumulation file, and each record was, on the average, 200 bytes in size, a pool size of (3 * 200 * 5000) or slightly less than 3 MB would hold all of the data. In practice, it isn’t necessary to allocate a pool this large since each buffer is reused once it has been freed by the recovery task. The point you are trying to achieve is to have enough buffer space so that change accumulation records for more than one recovery task are in storage at the same time.

 

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BMC AMI Backup and Recovery for IMS 5.1