Installation guide

Point of failure

The point in time when the most recent transaction log file (p. 57) existing in Exchange was created.

This is the most recent state Exchange data can be reverted to.

Storage group

In Exchange 2003/2007, a storage group is a logical container for Exchange databases (p. 55), the

associated transaction log (p. 57), checkpoint (p. 55), and other system files. All databases in a

storage group share a single log stream. A storage group is the basic unit for backup and recovery.

Starting with Exchange 2010, the concept of a storage group is discontinued. Therefore, you can

select individual databases for backup. Each database will be backed up along with the necessary

associated files.

Transaction log backup (Exchange)

A transaction log backup stores transaction log files (p. 57) along with checkpoint files (p. 55).

At first backup, Acronis Backup creates a regular full backup of the corresponding Exchange

information store (p. 56), storage group (p. 57) or database (p. 55). After that, only the log files and

checkpoint files are backed up. The transaction log files are truncated (p. 57) after each successful

backup. Circular logging (p. 55) must be disabled in Exchange, otherwise the backups will fail.

Having transaction log backups, you can revert Exchange data to any point in time. First, the data will

be recovered to the state saved in the full backup. Then, the transaction log will be applied.

Transaction log file (Exchange)

Transaction log files (.log) store all changes made to an Exchange database (p. 55) or storage group

(p. 57). Before committing any change to a database file, Exchange logs the change into a transaction

log file. Only after the change is securely logged, it is then written to the database. This approach

guarantees reliable recovery of the database in a consistent state in case of sudden database

interruptions.

Each log file is 1024 KB in size. When an active log file is full, Exchange closes it and creates a new log

file. A set of sequential log files is called a log stream. Each database or storage group has its own log

stream.

Transaction log file truncation (Exchange)

The process of deleting transaction log files (p. 57). Exchange truncates the transaction log files:

 After a successful full backup of the corresponding Exchange information store (p. 56), storage

group (p. 57) or database (p. 55) (excepting the copy-only (p. 55) backup).

 After a successful transaction log backup (p. 57).