Management of the bootstrap data set
The bootstrap data set (BSDS) is a VSAM key-sequenced data set that contains information about the log data sets and the records that those data sets include. The BSDS also contains information about buffer pool attributes.
The BSDS is defined with access method services when DB2® is installed and is allocated by a DD statement in the DB2 startup procedure. It is deallocated when DB2 terminates.
The active logs are first registered in the BSDS by job DSNTIJID, during DB2 installation.
To add a new active log data set or to delete an active log data set, you can use DSNJU003, the
change the log inventory utility. To use DSNJU003, you need to first stop DB2 and then restart it after the DSNJU003 job has completed. Alternatively,
you can add a new active log data set without stopping and starting DB2 by using the SET LOG command. Note that the SET LOG command does not support deletion of
an active log data set. 
Archive log data sets are dynamically allocated. When one is allocated, the data set name is registered in the BSDS in separate entries for each volume on which the archive log resides. The list of archive log data sets expands as archives are added, and the list wraps around when a user-determined number of entries is reached. The maximum number of archive log data sets that DB2 keeps in the BSDS depends on the value of the MAXARCH subsystem parameter. The allowable values for the MAXARCH subsystem parameter are between 10 and 10,000 (inclusive). If two copies of the archive log are being created, the BSDS will contain records for both copies, resulting in between 20 and 20,000 entries.
You can manage the inventory of archive log data sets with the change log inventory utility (DSNJU003).
A wide variety of tape management systems exist, along with the opportunity for external manual overrides of retention periods. Because of that, DB2 does not have an automated method to delete the archive log data sets from the BSDS inventory of archive log data sets. Thus, the information about an archive log data set can be in the BSDS long after the archive log data set is scratched by a tape management system following the expiration of the retention period of the data set.
Conversely, the maximum number of archive log data sets might be exceeded, and the data from the BSDS might be dropped long before the data set reaches its expiration date.
If you specified at installation that archive log data sets are to be cataloged when allocated, the BSDS points to the integrated catalog facility catalog for the information that is needed for later allocations. Otherwise, the BSDS entries for each volume register the volume serial number and unit information that is needed for later allocation.