RDF System Management Manual for H-Series RVUs (RDF 1.8)

2. Correct the problem on the backup system and recover the volume.
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 155).
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, a first purge, or
TOMATPOSITION, 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
the primary system has failed, you have executed an RDF takeover operation on your backup
system without RDF/ZLT, and you have subsequently brought you 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.
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.
128 Managing RDF