4.1. Reorganization considerations

The new DASD storage technology is characterized by:

  • Numerous high-capacity, small-size FBA, SCSI/SSA disks

  • Redundancy in different types of RAID

  • Generous amounts of cache, mainly to avoid the write penalty caused by RAID

  • Plenty of microcode in order to support RAID, cache algorithms, the mapping between the disks and the logical 3390/3380 volumes (as seen by z/OS), and in the RVA case, the virtualization of the 3390/3380

Because of that, all the old considerations to avoid long seeks and RPS misses in a 3390/3380 logical volume are out of date. Does this apply to VSAM KSDS need of reorganization? Let us look at all the performance reasons (old and new) justifying the VSAM reorganization.

4.1.1. CI/CA splits ...

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