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Appendix C. VSE/VSAM Considerations
VSE/VSAM support is not included in IXFP/SnapShot for VSE/ESA. This does not
mean however that you cannot take advantage of IXFP/SnapShot for VSE/ESA
with VSE/VSAM data sets.
It does mean that there is no support in IXFP/SnapShot for VSE/ESA to
dynamically adjust the VSAM catalog to reflect the target of the SnapShot copy.
However, through job control, a user catalog can point to the SnapShot copy and
access the data on the copy. In our test, we created a VSAM user catalog
(UCAT), space, and cluster on a volume at address 80E with serial number
PATEV1. We then snapped the volume to device address 80F with serial number
PATEV2, changing the volume serial number to PATEV1 in the process using the
following procedure:
1. Close any opened files on the volume. (This may include shutting down
CICS or other applications.)
2. Issue the following commands:
0 dvcdn 80f
ixfp snap,patev1:80f,vol1=patev1
0 dvcup 80f
3. The JCL to access the source volume is:
// DLBL UCAT01,′VOLSER.USER.CATALOG′,,VSAM
// DLBL DDNAME,′USER.FILE.ID′,,VSAM,CAT=UCAT01
4. To process data from the target volume, use the following JCL to access the
VSAM file:
// DLBL UCAT01,′VOLSER.USER.CATALOG′,,VSAM
// EXTENT SYS099,PATEV1
// ASSGN SYS099,80F,SHR
// DLBL DDNAME,′USER.FILE.ID′,,VSAM,CAT=UCAT01
// EXTENT SYS099,PATEV1
The first JCL finds the source volume because its device address is lower
than the target volume′s. The second JCL can only use the data from device
address 80F because we have explicitly pointed to that device with the
ASSGN statement. In this case, we can access the snapped copy of the
VSAM files on device 80F and copy it to the original volume, if required as
part of a recovery effort.
5. After using the target volume and its VSAM file, release the space back to
the RVA by issuing the ixfp ddsr 80f command. (Remember that 80F would
have to be DVCDNed before the IXFP DDSR command could be successfully
executed.) You can also retain it online for use in a VSE/ESA partition—as
long as the duplicate volume serial number and UCAT will not create a
problem.
Copyright IBM Corp. 1999 59