How data lifecycle management (DLM) deletes expired backup sets on disk-based storage

Last published : Apr 02, 2026
Backup Exec uses data lifecycle management (DLM) to automatically delete expired backup sets on disk storage, disk cartridge media, deduplication storage, storage arrays, virtual disks, and cloud storage. You specify how long to keep backup data when you create a backup job that is sent to a disk-based storage device. When the amount of time to keep the backup data expires, the data lifecycle management feature deletes the backup sets and reclaims the disk space unless there are dependent backup sets such as incrementals.
By default, Backup Exec keeps the most recent backup sets that are necessary to restore any backed-up component of a server, even if the backup sets expire. If backup sets are dependent on other backup sets, then Backup Exec does not delete the backup set until all expiration dates on the backup sets are reached. Even if the backup set is displayed as expired, the data is available until all dependent backup sets expire as well.
For example, you create a backup definition that contains a full backup and an incremental backup for the C: volume on a server. The first full backup runs, followed by the first incremental backup, and then the second incremental backup. The second full backup runs, followed by the third incremental backup, and then the fourth incremental backup. No more backups are run. All of the backup sets created by these backups eventually expire and are deleted by DLM. However, the backup sets that resulted from the second full backup and the third and fourth incremental backups are kept.
Backup Exec keeps these related backup sets because they are the most recent backup sets that you need to restore the C: volume. By keeping the last related backup sets, you have the data to restore the volume.
Warning: DLM deletes all expired backup sets that are created by a one-time backup job. DLM does not keep the last backup set after the retention date expires if the backup set is from a one-time backup.
To prevent the backup sets from being automatically deleted, you can manually retain specific backup sets or you can change the expiration date of the backup set. If you retain a backup set, Backup Exec then retains all dependent backup sets as well.
See Retaining backup sets on disk-based storage to prevent them from expiring.
See Changing the expiration date of backup sets on disk-based storage.
DLM searches for expired backup sets to delete from disk-based storage at the following times:
  • Every hour.
DLM starts for the first time 1 hour after you install Backup Exec and the Backup Exec service starts, and then runs every hour after that. If you restart the Backup Exec service, the hourly DLM cycle also restarts.
  • When the low disk space threshold for disk-based storage is reached.
The low disk space threshold is a storage device property. When the storage device's used capacity reaches this threshold, DLM immediately searches the device for the expired backup sets that it can delete.
  • When you manually expire a backup set.
When you manually expire a backup set on a standalone Backup Exec server, DLM runs immediately on the storage device on which the backup set is located. In a Central Admin Server feature (CAS) environment, if you manually expire a backup set from the central administration server, DLM immediately runs on the server on which the backup set was created. The server can be either the central administration server or the managed Backup Exec server. DLM runs only on the storage device from which the backup set was manually expired. If you manually expire a backup set from a managed Backup Exec server, DLM runs immediately on the storage device from which the backup set was manually expired.
To monitor the backup sets that data lifecycle management deletes, you can view the Backup Set Retention category in the audit log. You can also run the audit log report to view the backup sets that data lifecycle management deletes.
See Configuring audit logs.
See Audit Log report.
Storage options that can affect how data lifecycle management deletes backup sets are described in the following table:

Table: Storage options in Backup Exec that affect data lifecycle management

Storage option Description
Allow Backup Exec to delete all expired backup sets This global setting lets Backup Exec delete expired backup sets, even if they are the last remaining backup sets that you need to restore a server. Use this option when you want to delete backup data after a period of time. Alternatively, you can manually delete backup sets.
Warning: If you enable this option, the data that you need to restore a server may not be available.
The following conditions may cause you to lose backup sets when you enable this option:
- If the backup sets from the last full backup job expire before the next full backup runs. Ensure that when you create jobs, the backup sets are kept longer than the amount of time between full backups.
- If the backup job fails or is missed, and is not rerun before the backup sets expire. Monitor any failed or missed jobs, and ensure that you rerun them before the backup sets from the previous full backup expire.
Note: In a Central Admin Server feature (CAS) environment, this option is only available on the central administration server. If you enable this option on the central administration server, DLM deletes all expired backup sets on the central administration server as well as on all of the managed Backup Exec servers. This option deletes all expired backup sets on both centrally managed and locally managed Backup Exec servers in a CAS environment.
To access this option, click the Backup Exec button > Configuration and Settings > Backup Exec Settings > Storage .
See Editing global settings for storage .
Limit Backup Exec to read-only operations on a disk-based storage device if it has been detached for x number of days This global setting prevents Backup Exec from deleting expired backup sets on any disk-based storage device as soon as you reattach it. When you limit Backup Exec to read-only operations, you have time to review any expired backup sets and determine if you want to keep them before data lifecycle management deletes them. To keep expired backup sets, you can retain them or change the expiration date.
See Retaining backup sets on disk-based storage to prevent them from expiring .
See Changing the expiration date of backup sets on disk-based storage .
Backup Exec is limited to read-only operations only on the disk-based storage devices that are detached from the Backup Exec server for the specified number of days.
To access this option, click the Backup Exec button > Configuration and Settings > Backup Exec Settings > Storage .
See Editing global settings for storage .
Limit Backup Exec to read-only operations on a disk cartridge if it has not been inserted for x number of days This global setting prevents Backup Exec from deleting expired backup sets on any disk cartridge as soon as you insert it into a disk cartridge device. When you limit Backup Exec to read-only operations, you have time to review any expired backup sets and determine if you want to keep them before data lifecycle management deletes them. To keep expired backup sets, you can retain them or change the expiration date.
See Backup sets .
Backup Exec is limited to read-only operations only on the disk cartridges that are detached from the Backup Exec server for the specified number of days.
To access this option, click the Backup Exec button > Configuration and Settings > Backup Exec Settings > Storage .
See Editing global settings for storage .
Limit Backup Exec to read-only operations This device property prevents data lifecycle management from running on a specific disk-based or disk cartridge storage device that you reattach or reinsert it. This option applies only when the storage device has been absent from the Backup Exec server for the number of days that you specify in either of the two previous global settings described in this table.
To access this option, on the Storage tab, right-click the device, click Details , and then click Properties .
See Editing disk storage properties .
See Editing disk cartridge properties .
See Editing the properties of a deduplication disk storage device .
Low disk space This device property is the first of three low disk space conditions. When the storage device's used capacity reaches this threshold, the data lifecycle management feature immediately searches the device for expired backup sets that it can delete.
Data lifecycle management also runs on a disk cartridge if the cartridge reaches capacity during a backup job. The backup may not need to span to another cartridge if data lifecycle management deletes enough expired backup sets. If a job does span and you insert a new disk cartridge that is full, data lifecycle management deletes expired backup sets on the new cartridge.
To access this option, on the Storage tab, right-click the device, click Details , and then click Properties .
See Setting low disk space thresholds on disk-based storage .
For information about the best practices of Backup Exec data lifecycle management (DLM) feature, refer to Backup Exec Best Practices.