IBM SC34-7012-01 manual Example of recovery using volume backup

waits for indoubt resolution before allowing general access to the data set. In such a situation you can still release the locks immediately, using the SET DSNAME command, although in most cases you will lose data integrity. See “Lost locks recovery” on page 89 for more information about resolving indoubt UOWs following lost locks processing.

Example of recovery using volume backup:

In this example, we simulated the recovery from the loss of a volume by performing a volume restore before the forward recovery process. Backout-failed UOWs were the result of the I/O errors that occurred when the volume failed.

Note: It is important to ensure that CICS cannot retry the shunted UOWs when the volume is restored, until after the forward recovery work is complete. This is done by quiescing the volume before it is restored, as described under “Volume recovery procedure using CFVOL QUIESCE” on page 190 (step 1).

Many of the steps in this second example are the same as those described under the “Example of recovery using data set backup” on page 192, and are listed here in summary form only.

1.We simulated the volume failure using the MVS command.

ROUTE *ALL,VARY 4186,OFFLINE,FORCE

2.We stopped the I/O errors by closing the files that were open against failed data sets. In our example, file F04DENDB was open against data set RLSADSW.FV04D.DATAENDB and file F04DCTRL was open against data set RLSADSW.FV04D.TELLCTRL.

3.Because the failed data sets were restored from the same volume, there was no need to delete the catalog entries for these data sets.

4.Before restoring the failed volume, we quiesced the volume to ensure that CICS could not access the restored data sets. by issuing the command:

VARY SMS,CFVOL(9S4186),QUIESCE

In this example, for volume serial 9S4186, the command produced the message:

IGW462I DFSMS CF CACHE REQUEST TO QUIESCE VOLUME 9S4186 IS ACCEPTED

We confirmed that the volume was quiesced by issuing the MVS command:

DISPLAY SMS,CFVOL(9S4186)

which confirmed that the volume was quiesced with the message:

IGW531I DFSMS CF VOLUME STATUS VOLUME = 9S4186

DFSMS VOLUME CF STATUS = CF_QUIESCED

VOLUME 9S4186 IS NOT BOUND TO ANY DFSMS CF CACHE STRUCTURE

5.We simulated the volume restore for this example by using the MVS VARY command to bring the volume back online:

ROUTE *ALL,VARY 4186,ONLINE

Because the volume was quiesced, attempts to open files on this volume failed, with messages such as the following:

DFHFC0500 ADSWA02A RLS OPEN of file F04DENDB failed. VSAM has returned code X’0008’ in R15 and reason X’00C6’.

6.The impact of the recovery process is greater if there are inflight tasks updating RLS mode files. To minimize the impact, you are recommended at this point to quiesce all data sets that are being accessed in RLS mode.

7.We terminated the SMSVSAM servers with the MVS command:

196CICS TS for z/OS 4.1: Recovery and Restart Guide