"SARPAC" is generally used to consolidate tapes which have few active reports. The number of active reports is matched to the number or reports written to the tape when it was originally created. When this percentage of active reports falls below the client specified threshold (PTHRESH), the tape will become eligible for consolidation. Tapes may also be consolidated based on client directed orders such as tape sequence number, tape sequence number range and/or storage group name.
SARPAC functions in two phases.
Phase 1, SARPAC will build a table of all tapes defined in the database. It will then build a table associated with each tape as in the order of file position. This is done for two reasons, one to see how many reports are active on a tape and two SARPAC will consolidate based on tape sequence and file position not alphabetic sequence. Once these tables are built, SARPAC can determine what work needs to be done.
Phase 2, SARPAC will select the tapes which meet the clients specified consolidation criteria, and begin moving the report to new output tapes. The original input tapes will then be considered empty and will be eligible for deletion during the next backup cycle.
Both phases are necessary, the actual printing of the tape report takes very little time; it's the work of building the tales which require processing time. This time is directly proportional to the number of tapes/reports in the database and the fragmentation of the Master Index. If the Master Index contains a lot of empty blocks, it could drastically extent the processing time of Phase 1.