For all processing of non-VSAM data sets, and reporting on VSAM components with SCAN REALVOLS, REPORT COMPONENTS, the value of MODIFIED is set to YES/TRUE/ON if the change bit DS1IND02 is set in the Format-1 DSCB for each data set or component.
For all other processing of VSAM clusters, the value of MODIFIED is set to YES/TRUE/ON if the CA Disk Files data set shows that this cluster has never been backed up or archived by CA Disk, or if the last modified date and time in field AMDSTSP in the catalog entry for each cluster are more recent than the last CA Disk backup or archive of the clusters, or if the VSAM cluster open flag in catalog field OPENIND is on. The OPENIND flag is set ON whenever a VSAM cluster is open and set OFF when it is closed. If the cluster is not closed normally (that is, when a system crash occurs), then its flag is left on. Even if the comparison of last modified date/time and last backup date/time indicates the data set has not been modified since its last backup, the OPENIND flag test will indicate that MODIFIED is YES/TRUE/ON.
Note: If a VSAM cluster is currently in use, normal system enqueues will ensure that CA Disk does not get access to the data set when the OPENIND is ON.
Because CA Disk must check the FILES for each cluster, using this parameter with VSAM clusters can increase processing time.
Note: Certain applications bypass normal OPEN processing. Non-VSAM data sets updated by these applications will not have their change bits on. The following SELECT statement will never select these data sets:
SELECT CRITERIA=(MODIFIED,EQ,YES)
To select all potentially modified data sets, you must specifically select these data sets.
VSAM clusters used by these applications (that is, DB2) will have a last modified date of 00/00/0000 or 0. In this case, the last use date for the primary data component will be used in comparison with the date of the last backup. The change bit for the primary data component must also be on.
|
Copyright © 2015 CA Technologies.
All rights reserved.
|
|