Before the introduction of zEDC, using host based compression when migrating directly to tape was not recommended because of the MIPS required to compress the data. The same compression results could be achieved through tape control unit compression without consuming MIPS.
With zEDC, a significant savings can now be achieved by first compressing the data because of the significant reduction in the number of blocks that are processed by DFSMShsm. Besides reducing the MIPS consumption by up to 15%, elapsed time may be reduced by as much as 25%. Also, since zEDC can achieve a higher compression ratio than a tape control unit, virtual tape space may be reduced by as much as 37%. The reduction in the number of blocks written to tape also reduces the overall MIPS and elapsed time required for RECYCLE processing.
(Be sure to apply APAR OA48394 before enabling zEDC for DFSMShsm data written directly to tape. This development APAR provides an algorithmic improvement that provides these MIPS and elapsed time improvements that will only be achieved after this APAR has been applied).
Recall also offers MIPS and elapsed time improvements. Recalling zEDC compressed ML1 data has shown a 69% reduction in MIPS. Recalling zEDC compressed data from ML2 virtual tape has shown a reduction of 11% in MIPS and 32% in elapsed time.
Similar results can be achieved when using zEDC for data set level backup and recovery.
With zEDC and z/OS V2R1 or higher in your environment, enable DFSMShsm usage by simply adding the SETSYS ZCOMPRESS(ALL) setting to your DFSMShsm PARMLIB member and watch the immediate improvement!