BWO and concurrent copy
Concurrent copy improves BWO processing by eliminating the invalidation of a BWO dump because of updates to the data set.
The following is a comparison of various kinds of dumps that
you can request:
- Normal dump. Use of the data set must be quiesced so that serialization is obtained, the data set is dumped, and serialization is released. The data set cannot be used for the entire time.
- Concurrent copy dump. Use of the data set must be quiesced so that serialization is obtained, concurrent copy utilization is completed within a very short time (compared with the actual time to dump the data set), serialization is released, and the data set is dumped. The data set can be used after concurrent copy initialization is complete.
- BWO dump. Serialization is attempted but is not required, and the data set is dumped. If it is eligible for BWO, the data set is dumped without serialization and can remain in use for the entire time, but the dump can be invalidated by update activity to the data set.
- BWO dump using concurrent copy. Serialization is attempted but is not required, concurrent copy initialization is completed, and the data set is dumped. If it is eligible for BWO, the data set is dumped without serialization and can remain in use for the entire time, and updates that occur do not cause the dump to be invalidated.
To use concurrent copy, specify the CONCURRENT keyword when you use DFSMShsm to dump BWO data sets.