On Thu, 26 Mar 2009 13:22:01 -0400, Lizette Koehler <[email protected]> wrote:
>I am going to be doing an analysis on our tapes to see if they are optimally blocked. We are using VTS that looks like 3490E tapes. > >Is there a good rule of thumb for all datasets on tape - that to be blocked optimally use X? > >The lrecls on these tape range from 80 to 10399 > >Lizette > For tape (especially modern tape), I've always here that the optimal BLKSIZE is as big as you can make it. For "normal" VB files that would be 32767. For FB files, the largest multiple of the LRECL <= 32767. IIRC, there are some products which can exceed this. But the QSAM/BSAM access method is stuck at 32767. At least until somebody tells me that I am totally out of date, again. -- John ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
