This parameter is used with the backup disk command unless the --use_vss parameter value is acronis or none.
If the parameter is specified, logs of Microsoft Exchange Server and of other VSS-aware applications (except for Microsoft SQL Server) will be truncated after each successful full, incremental or differential backup.
Do not specify this parameter in the following cases:
If you use Acronis Backup & Recovery 11.5 Agent for Microsoft Exchange Server or third-party software for backing up the Exchange Server data. This is because the log truncation will interfere with the consecutive transaction log backups.
If you use Acronis Backup & Recovery 11.5 Agent for Microsoft SQL Server (single-pass) for backing up the SQL server data. To truncate the SQL Server log after a single-pass backup, specify the --mssql_truncate_logs parameter.
If you use third-party software for backing up the SQL Server data. The reason is that the third-party software will take the resulting disk-level backup for its "own" full backup. As a result, the next differential backup of the SQL Server data will fail. The backups will continue failing until the third-party software creates the next "own" full backup.
If other VSS-aware applications are running on the machine and you need to keep their logs for any reason.