Extended Functions terminology
IMS Database Recovery Facility Extended Functions includes several unique terms that you should understand before you begin to use the tool.
- Change Accumulation (CA) data set
- Data set created by a database change
accumulation utility run that contains all of the database updates between the last image copy and
the time the CA utility completed.
There are two basic kinds of CA data sets:
- Complete CA data sets (based on available system log data sets (SLDS)).
- Incomplete CA data sets that are created at the time that CA utility was generated and when the required SLDS are not yet available.
- Disaster recovery site (DR)
- Location at which data sets necessary to recover IMS databases are located in the event of a disastrous IMS outage such as natural calamities, fires, power failures, or other disasters.
- Full recovery
- Recovery of a database using the most current information available: image copy (IC), CA, Logs.
- IMS command (IMSCMD)
- This feature allow you to issue IMS commands in batch.
You can view the output of the commands that is returned in a report file.
- IMS Database Recovery Facility
- IMS database tool that can recover databases using Full Recovery, Time Stamp Recovery, or Point In Time Recovery.
- Point-in-time recovery (PITR)
- Timestamp input to which a database can be
restored.
The database was typically allocated and being accessed at the selected recovery timestamp.
- RECON cleanup (RCU)
- This feature allows you to prepare a set of RECON data sets for your disaster recovery environment by modifying the contents of the RECONs to match their DR site.
- Recovery health check (HCHECK)
- The HCHECK function consists of many
different options to check and verify the recoverability of your environment.
The majority of these options interrogate and verify information in the RECON data sets, and compare the information in the RECONs with information that is outside of the RECONs (like information that is in the system catalog and in other places).
You can specify each piece of information that you want checked. And you can exclude the pieces of information that you do not want checked.
HCHECK uses information from:
- RECON data sets.
- IMS Recovery Expert repository for System Level Backups (SLBs).
- MVS catalog.
- Recovery point
- Timestamp that can be used as input to database recovery utilities such as IMS Database Recovery Facility or the standard IMS Recovery utility DFSURDB0, as a time to which a database can be restored.
- Recovery point create (RPCR)
- This feature allows you to create a recovery
point for one or more databases by issuing synchronized /DBRECOVERY or /DBDUMP commands for the
databases, waiting for the databases to be deallocated on all of your IMS systems, and then optionally restarting them.
You can also optionally perform a synchronized log switch on all active IMS systems in the group with RPCR.
- Recovery point identification (RPID)
- This feature interrogates information in the RECON data sets to determine common recovery points for one or more databases.
- Recovery time range (RTR)
- RPID input parameter containing two times within which the search for recovery time spans and recovery points is bounded.
- Recovery time span (RTS)
- Span of time within which recovery points can be selected and to which a database or group of databases can be recovered.
- System Level Backup (SLB)
- The System Level Backup (SLB) is created by IMS Recovery Expert and is an instantaneous backup of the IMS system including the IMS
database data sets.
The SLB can be used to recover all or part of the IMS system and can create image copies that are used as input to IMS Database Recovery Facility recovery functionality.
- Timestamp recovery (TSR)
- Timestamp input to either IMS Database Recovery Facility or another standard database recovery program
such as DFSURDB0.
The database is typically offline at this timestamp.
In the RPID documentation, TSR refers to non-PITR timestamps, though PITR is actually a special case of TSR.
- Verify recovery assets (VERIFY)
- The VERIFY function interrogates the RECON
data sets and first generates a list of the recovery assets that are needed in
order to recover one or more databases.
When this list is generated, this feature provides options to perform the following tasks:
- Print the list.
- Allocate each asset to ensure that it exists.
- Open each recovery asset that exists to ensure that it is valid.
VERIFY uses information from:
- RECON data sets.
- IMS Recovery Expert repository for System Level Backups (SLBs).
- MVS catalog.