Manually deleting archive log data sets

You must keep all the log records as far back as the lowest RBA identified in messages CSQI024I and CSQI025I. This RBA is obtained using the DISPLAY USAGE command that you issued when creating a point of recovery using Method 1: Full backup. Read Creating a point of recovery for non-shared resources before discarding any logs.

 

Locate and discard archive log data sets

Having established the minimum log RBA required for recovery, we can find archive log data sets that contain only earlier log records by performing the following procedure:

1. Use the print log map utility to print the contents of the BSDS. For an example of the output, see The print log map utility (CSQJU004).

2. Find the sections of the output titled "ARCHIVE LOG COPY n DATA SETS". If you use dual logging, there are two sections. The columns labeled STARTRBA and ENDRBA show the range of RBAs contained in each volume. Find the volumes whose ranges include the minimum RBA you found with messages CSQI024I and CSQI025I. These are the earliest volumes we need to keep. If you are using dual-logging, there are two such volumes.

   If no volumes have an appropriate range, one of the foloowing cases applies:

   • The minimum RBA has not yet been archived, and we can discard all archive log volumes.

   • The list of archive log volumes in the BSDS wrapped around when the number of volumes exceeded the number allowed by the MAXARCH parameter of the CSQ6LOGP macro. If the BSDS does not register an archive log volume, that volume cannot be used for recovery. Therefore, consider adding information about existing volumes to the BSDS. For instructions, see Changes for archive logs.

     Also consider increasing the value of MAXARCH. For information, see the WebSphere MQ for z/OS System Setup Guide.

3. Delete any archive log data set or volume whose ENDRBA value is less than the STARTRBA value of the earliest volume you want to keep. If you are using dual logging, delete both such copies.

   Because BSDS entries wrap around, the first few entries in the BSDS archive log section might be more recent than the entries at the bottom. Look at the combination of date and time and compare their ages. Do not assume that we can discard all entries above the entry for the archive log containing the minimum LOGRBA.

   Delete the data sets. If the archives are on tape, erase the tapes. If they are on DASD, run a z/OS utility to delete each data set. Then, if you want the BSDS to list only existing archive volumes, use the change log inventory utility (CSQJU003) to delete entries for the discarded volumes. See Changes for archive logs for an example.