Every time you deal with a block you execute a bit of code to deblock the records. To fill a Mod 9 volumes to test TDMF I copied a large dataset with a small block size to a dataset with half track blocking on a spare volume, then copied the first data set to several other datasets to fill the volume. The first copy to the half track blocksize took about 10 minutes. The subsequent several copies ran much faster and also took about 10 minutes.
On Fri, May 19, 2017 at 1:03 PM, Lizette Koehler <[email protected]> wrote: > List - > > I have gone through a few manuals and cannot determine the answer to the > following questions. Any guidance is appreciated > > 1) Can the SDB be adjusted from half-track to another setting (quarter or > full)? > 2) Are there any new best practices for SDB that have changed in the last > 20 > years? > 3) Is Half-track still considered OPTIMUM? > > Since the storage arrays are so fast, I would think that maybe full track > would > not be that much of a performance impact any more. > > I have been working offlist with a couple of people with JCL and BLKSIZE and > SPACE Sizing. I am trying to figure out how to make the formula more > accurate. > When I calculate space - I use full trace blocking. However, I find when SDB > uses half-track, my math is off. > > Any thoughts or help would be great. > > > Lizette Koehler > statistics: A precise and logical method for stating a half-truth inaccurately > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN -- 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
