TMF Introduction (G06.26+)

Transaction Protection and Database Recovery
HP NonStop TMF Introduction—522414-002
3-2
Audit Trails
Audit Trails
An audit trail is a series of files that TMF uses to record sequential information about a
transaction’s changes to an audited file. Only TMF can rename, purge, or alter audit-
trail files.
The disk volumes that contain audit trails are called active-audit volumes. HP requires
that you place audit trail files and audited database files on separate disk volumes so
that the database files and audit-trail files cannot be damaged by the same failure.
The volumes where audited database files reside are called data volumes.
Figure 3-1 illustrates the contents of audit records and associated database files for a
transaction that deposits $550 to the Lee checking account, and $100 to the Lee
savings account. In this figure, the checking and savings database files reside on
audited volumes on disks $DB1 and $DB2; the audit-trail files reside on a separate
disk, $AUDIT.
Figure 3-1. Audit-Trail Records
AA001002
TX1 (CHECKING)
BEFORE LEE $250
AFTER LEE $800
TX1 (SAVINGS)
BEFORE LEE $100
AFTER LEE $200
TX1 COMMIT
•
•
•
AA001001
$AUDIT
CHECKING
ADAMS
LEE
WOOD
$450
$800
$250
$DB1
$DB2
SAVINGS
BROWN
LEE
WHITE
$400
$200
$600
VST013.vsd