TMF Planning and Configuration Guide (H06.05+)

HP NonStop TMF Planning and Configuration Guide—540136-002
5-1
5
Configuring TMF for Backup and
Recovery
This section describes the TMF aspects of backup and recovery. It contains the
following topics:
TMF does not require you to make backups of your database or audit trails. However,
to take full advantage of the features of TMF, it is advisable to do so. In addition, to
ensure that TMF properly protects transactions:
•
Your application code must include transaction control statements to begin, end
(commit), and abort (rollback or back out) transactions, and must also include
appropriate data-locking techniques for the transactions.
•
You must provide sufficient disk space for audit trails.
Backup and Recovery Features of TMF
TMF automatically protects all audited database files by providing the following
features:
•
Automatic backout of transactions
•
Automatic volume recovery
•
Maintenance of audit-trail information for use in file recovery from online dumps
Automatic Transaction Backout
The TMF backout process is automatically created when you start TMF. When a
transaction is aborted, TMF uses the before-images in the audit trails to back out the
transaction; in other words, it reverses the effects of the transaction. TMF can back out
transactions without affecting database consistency because the record locks and two-
phase commit feature prevent transaction interaction, maintaining locks on data until
the backout completes.
You can view the status of transactions by using the STATUS TRANSACTIONS
command. Transactions that are being backed out are in the aborting state.
Topic Page
Backup and Recovery Features of TMF 5-1
Strategies for Online Dumps and Audit Dumps 5-2
Configuration Options for Backup and Recovery 5-8
Recovery Planning for Catastrophic Failures 5-14