On Tue, Aug 21, 2012 at 12:14 PM, retired mainframer <[email protected]> wrote: > :>: -----Original Message----- > :>: >From: Uriel Carrasquilla <[email protected]> > :>: >Sent: Aug 20, 2012 2:34 PM > :>: >To: [email protected] > :>: >Subject: Re: HSM - space for full recall > :>: > > :>: >We have all the HSM ML2 on VTL and the VTL guy is telling me that I am > :>: using 70 TBytes. > :>: >I believe I am using 40 TBytes. > > Any chance one of you is measuring thingamajigs and the other doohickeys? > > A card image dataset with 10 records contains 800 bytes of data but occupies > one track. One thousand of these contain 800KB but consume 5.6MB of 3390 > DASD. It can get even worse if there are unused tracks in the last extent > or if the dataset needs to be reorganized (e.g., compress the PDS). > > If the 70TB is based on tracks and the 40TB on content, there might not be a > discrepancy. > > (And yes, I was surprised that both words passed the spell checker.) > When you recall a dataset, you get the exact amount required (some rounded up to the next cylinder) and the PDSs are compact (no deleted members).
You still have inefficient blocksizes and unused tracks in the last cylinder and VSAM datasets are full sized and uncompressed. -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
