Updating the Catalog After Recovery

After you recover a catalog, use the access method services DIAGNOSE command to help determine how the recovered catalog differs from the current status of data sets, VVDSs, and BCSs on your system. Some activities that alter data sets will change the information in the BCS or VVDS records, and you will need to update your catalog to reflect any changes which have occurred since the catalog was last backed up.

The DIAGNOSE command identifies differences between BCS and VVDS records for VSAM and SMS-managed non-VSAM data sets. To identify inaccurate BCS records for other non-VSAM data sets, use LISTCAT NONVSAM, if possible, before and after the recovery.

The access method services DEFINE and DELETE commands can be used to update the catalog. With these commands, you can: recatalog a data set, thus updating the information in the catalog records; delete a data set; delete a data set's record in the BCS or VVDS; and delete a data set's DSCB in the VTOC.

Table 1 shows the activities that might have occurred since the last catalog backup, and the tasks required to update the catalog.

Table 1. Activities That Downgrade a Basic Catalog Structure (BCS)
Activity Causing Downgrading	Data Set Type	Location of Information	Action Needed To Update the Catalog
Add
Records	N V	VTOC/tape labels VVDS	None
Extents	N V	VTOC/tape labels VTOC/VVDS	None
Volumes	N V	BCS/VTOC/tape labels ¹ BCS/VTOC/VVDS	Recatalog the data set ²
Candidate Volumes	V	BCS	Add the volume with ALTER ADDVOLUMES
Data Sets	N V	BCS/VTOC/tape labels ¹ BCS/VTOC/VVDS	Recatalog the data set ²
Remove
Records	N V	VTOC VVDS	None
Extents	N V	VTOC VTOC/VVDS	None Not applicable to VSAM
Volumes	N V	BCS/VTOC ¹ BCS/VTOC/VVDS	Recatalog the data set ² Not applicable to VSAM
Candidate Volumes	V	BCS	Remove volume with ALTER REMOVEVOLUMES
Data Sets	N V	BCS/VTOC/tape labels ¹ BCS/VTOC/VVDS	DELETE NOSCRATCH to remove BCS record
Modify
Records	N V	(data set only) VVDS	None
Extents	N V	VTOC VTOC/VVDS	None Not applicable to VSAM
Volumes	N V	BCS/VTOC/tape labels ¹ BCS/VTOC/VVDS	Recatalog the data set ² Not applicable to VSAM
Data Sets	N V	BCS/VTOC ¹ BCS/VTOC/VVDS	Recatalog the data set ²
Notes: N Non-VSAM data set V VSAM data set SMS-managed non-VSAM data sets also have VVDS entries. To recatalog a data set, first use DELETE NOSCRATCH to remove BCS record for the data set. Then, use DEFINE to recreate the entry. If the data set is VSAM or SMS-managed, specify RECATALOG on the DEFINE command, so that the BCS record is rebuilt using information from the VVDS.