TMF Introduction (G06.26+)

Transaction Protection and Database Recovery

HP NonStop TMF Introduction—522414-002

3-6

Audit Dumps

Eventually, as TMF writes more and more audit records, the amount of space required

for audit records in the audit trail could exceed the disk space available for them. As

transactions are committed, the need decreases for volume recovery to use audit

records pertaining to the oldest committed transactions; file recovery, however,

typically needs these records. To free disk space for current audit records, and to

preserve the availability of older audit records, TMF copies audit-trail files to audit

dumps.

These dumps can be written to secondary storage media at either the local site or a

remote site. For a dump to tape, TMF prompts the operator to mount a scratch tape

when an audit-trail file is ready for dumping. For extra security, TMF can write

duplicate, simultaneous dump tapes: the business can then keep one or more sets of

tapes off site for protection if a fire or other disaster damages an installation.

To preserve an audit trail at an unattended site, a good technique is to perform audit

dumps on a remote disk. The audit trail could be dumped to disk at a remote, attended

site, and then be backed up to tape.

A site should store audit dumps for possible future use. A site that does not dump and

preserve audit trails will not be able to perform file recovery.

Automatic Audit Dumping

Those who are responsible for configuring a TMF system may configure audit trails to

be dumped automatically or may dump audit trails as needed. HP recommends that

you configure automatic audit dumping to ensure the highest levels of protection.

Automatic audit-dumping for an audit trail is illustrated in Figure 3-3. When audit-trail

file AA000005 becomes full, TMF begins writing to the next audit-trail file, AA000006.

AA000005 is dumped to secondary storage media. Once the file has been dumped,

the original file on the audit volume is marked as dumped and eligible for renaming

when needed for new audit information.