The SPHERE is needed when dumping VSAM. If this is PS it is not needed
Second, the default, OPTIMIZE(1), reads one track at a time. OPTIMIZE(2), (3),
or (4) results in less elapsed time and fewer I/O operations on the DASD device
whenever the load on the tape channel is low enough and the tape speed is high
enough to keep pace with the data being read from the DASD volume. To obtain
the best performance with DFSMSdss and 3592's, specify OPTIMIZE(4).
So I would try adding OPTIMIZE(4) to your control cards and remove the SPHERE
unless you are dumping VSAM.
I am not sure why the BLKSIZE is of concern. I would work on optimizing DFDSS
to run at its best. Remember DFDSS will probably add to your output file
certain key information it needs to restore the file.
For a physical dump, each logical volume of a DFSMSdss dump data set contains
the following data in the following sequence:
Volume header record, which identifies and contains data pertinent to the
whole volume and identifies the type of operation that created the dump.
Map record or records, which map the tracks that were dumped. The data in
this record is described by the ADRBMB Data Area.
Track 0: dump of track 0 of cylinder 0.
VSAM volume data set (VVDS) track records, if VSAM or SMS-managed data sets
exist on the volume and were dumped.
Volume table of contents (VTOC) track records.
Data track records, which include VVDS if it is part of the dump. This item
is repeated for all tracks being dumped.
Two volume trailer records, which identify the end of the data for the DASD
volume.
For a logical dump, the format of the DFSMSdss dump data set contains the
following data in the following sequence:
Tape header record.
List of potential data sets record.
Data set header record.
Volume header record (one for non-VSAM data sets, one for each VSAM
component).
Sphere information record (if the SPHERE keyword was specified and this
data set is part of a sphere).
Data track records (one or more for each track of the data set on this
volume).
Two data set trailer records.
So, I am still trying to understand your problem with BLKSIZE. What
specifically is the issue? If it is performance, then the OPTIMIZE should help.
DFDSS output dump file does its own process. I have coded my own BLKSIZE on a
Dump output. It did not matter. DFDSS did what it felt was correct.
Lizette
> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On
> Behalf Of Victor Zhang
> Sent: Tuesday, May 06, 2014 9:10 PM
> To: IBM-MAIN@LISTSERV.UA.EDU
> Subject: Re: Change tape block size
>
> Lizette,
> Here it is:
> For PS dataset:
> DUMP -
> OUTDDNAME(ODD) -
> DATASET(INCLUDE(TEST.DATA)) -
> TOL(ENQF) SPHERE
>
> For SMS compact extended format dataset:
> DUMP -
> OUTDDNAME(ODD) -
> DATASET(INCLUDE(TEST.AB2F.**)) -
> TOL(ENQF) SPHERE
>
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