RDF System Management Manual for J-series and H-series RVUs (RDF Update 13)

3. From the backup system, restart TMF on the backup system by entering this command through
TMFCOM:
~START TMF
4. From the primary system, resume updating of the backup database by entering this command
through RDFCOM:
]START UPDATE
Volume Recovery Processing
RDF handles volume recovery automatically.
Volume Recovery Failure
RDF cannot recover from a TMF subsystem failure if TMF cannot successfully perform volume
recovery. After the TMF failure has been resolved, you must perform the following tasks:
1. Resynchronize the primary and backup databases, following procedures explained in Chapter 6
(page 147) and Chapter 7 (page 157).
2. Reinitialize RDF.
File Recovery on the Primary System
A file recovery operation occurs whenever a TMFCOM RECOVER FILES command is issued at the
primary system. A simple file recovery operation does not affect RDF nor does it require database
synchronization. A file recovery operation to a timestamp or a first purge, however, does require
you to stop RDF, reinitialize, and resynchronize the affected files.
The file recovery TOMATPOSITION is a special usage that achieves synchronization itself. If your
RDF primary system has failed, you have executed an RDF takeover operation on your backup
system without RDF/ZLT, and you have subsequently brought your primary system back online,
you can resynchronize the database on your recovered primary system with file recovery
TOMATPOSITION. When the takeover has completed on your backup system, RDF normally logs
an RDF event 888. This event provides you with a master audit trail sequence number and relative
byte address that you can use for file recovery TOMATPOSITION on your recovered primary
system. The result of this operation puts the database on your primary system into synchronization
with the database on your backup system at the time when the takeover operation completed. If
you started application processing on your backup system after the completion of the takeover
operation, you then need to configure a new RDF subsystem to replicate all changes made to the
database on your backup system to the database on your primary system.
WARNING! File Recovery with TOMATPOSITION should only be used when recovering your
primary system after an RDF Takeover operation on your backup system. If you use the
TOMATPOSITION for any other reason, it will require database synchronization just like File
Recovery to a timestamp or first purge.
File Recovery on the Backup System
You are encouraged to take online dumps on your backup database on a regular basis for the
following reasons:
• If you have lost your primary system and have taken over on your backup system, the online
dumps can be used for any type of file recovery operation provided the redo end point is
located after all audit data that was generated during the RDF takeover. For example, a file
recovery to a timestamp must be to a timestamp after the time when the RDF takeover
completed.
• If RDF is running from your primary to your backup system and you lose one or more disks
on your backup system, you should stop the RDF updating, perform a simple file recovery on
the backup system to recover the files on the affected disks, and then restart RDF updating.
Responding to Operational Failures 119