Filter
Top Products
After an uncontrolled or immediate shutdown, further BWO backups might be
taken by DFSMShsm, because the BWO status in the ICF catalog is not reset. These
backups should be discarded; only the non-BWO backups taken at the end of the
batch window should be used during forward recovery, together with the CICS
forward recovery logs.
Data set security: CICS must have RACF ALTER authority for all data sets that are
defined as BACKUPTYPE(DYNAMIC), because CICS needs to update the BWO
attributes in the ICF catalog. The authority must apply either to the data set or to
the ICF catalog in which the data set is cataloged. For information on defining
RACF ALTER authority, see the CICS RACF Security Guide.
BWO processing
The information in the remainder of this section might be required by the system
administrator to recover from error situations due to incorrect operating
procedures or hardware failures.
The main data fields used by the BWO facility are:
v Attribute flags in the ICF catalog, to control BWO activity. The DFSMSdfp field
dictionary name is VVRSMFLG. For more information about the attribute flags
used in connection with BWO, see DFSMS/MVS Managing Catalogs.
v Recovery point in the ICF catalog. This point is the time from which the forward
recovery utility must start applying log records. It is always before the time that
the last backup was taken. It is recorded in local time format (0CYYDDDF
HHMMSSTF) where:
C = century (0=1900, 1=2000, etc.)
YY = year
DDD = day
HH = hours
MM = minutes
SS = seconds
T = tenths of a second
F = + sign
The DFSMSdfp field dictionary name is VVRRDATA.
v The BACKUPTYPE attribute in the CICS file resource definition (for DFSMS 1.2),
or the BWO option in the ICF catalog (for DFSMS 1.3). When CICS has
determined the BWO option from one of these sources, it stores the value into
the data set name block (DSNB) for the base cluster at the time the first file
referencing the data set is opened.
The attribute flags and recovery point are managed by VSAM in the primary data
VSAM volume record (VVR) of the base cluster, which is in the VSAM volume
data set (VVDS). There is only one primary base cluster VVR for each VSAM
sphere, which is why BWO eligibility is defined at the sphere level. For more
information, see DFSMS/MVS Managing Catalogs.
BWO processing affects the following operations in a CICS system:
v File opening
v File closing
v Shutdown and restart
v Data set backup and restore
v Journaling and forward recovery logging
v Forward recovery
Chapter 18. Backup-while-open (BWO) 209