HP XP Array Manager Software - Manual (Page 391)

Figure 19 Flow of operation using transaction logs (Roll-forward)
After the database is backed up from the primary volume to the secondary volume at point A, the
database is updated at point B. If an error occurs in a data file on the primary volume at point C and
then the database is restored from the secondary volume to the primary volume, the database returns
to the state it was in at point A. In this case, if the transaction logs from when the backup was executed
up until the time of the restore are stored on the primary volume, the database can be recovered to
the state immediately before the error occurred (point C) using the roll-forward option.
Example of a roll-forward restore (Exchange 2003/2007)
This example describes restoring only the data in the mailbox store (information store) out of the
backup data obtained from the secondary volume to the primary volume, and rolling forward
transaction logs. (When a restore is executed in units of information stores, you must roll forward
transaction logs at the time of restoration.)
User Guide 391