Data Lifecycle Management (DLM) Backup Chain and Dependency Rules
Article ID: 100032333
Updated On:
Description
Last Recovery Chain Rule
An expired backup set will not be deleted by DLM if it is part of the last copy of the most recent recovery chain.
- A recovery chain is the group of backup sets required for point-in-time recovery of a particular resource
- The last copy to expire for backup sets for every backup job are maintained even after the retention period has expired
- Manually expiring backup set over rides this rule
- Can be disabled from Settings > Storage > Data Management
Note: The last available backup for any resource will be automatically deleted when it passes the expiry date when this rule is disabled by marking the checkbox for “Allow Backup Exec to delete all expired backup sets”
This is one of three main DLM Retention Rules.
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Dependency Rules
An expired backup set will not be deleted by DLM if it has one or more unexpired or retained dependent sets.
Dependency calculations are based on four rules:
- Backup Chain Dependents
- With no mixed Incremental/Differential sets
- Mixed Incremental/Differential sets
- When Copy Exists
- Last Copy to Expire
- Simplified Disaster Recovery (SDR) Backup Sets
For backup sets created by Backup Exec 2010 R3 and earlier:
- A single *.BKF could contain multiple backup sets
- If the *.BKF contains at least one backup set that cannot be deleted due to DLM rules then
- The entire *.BKF is maintained
- Other backup sets in the *.BKF will not get deleted
Backup Chain Dependents Rule
An expired backup set cannot be deleted by DLM unless all its dependent sets in the backup chain are expired and deleted.
Backup chain dependents calculation with no mixed incremental/differential sets is based on:
- Full depends on no other set
- Incremental depends on previous full and incremental backup sets
- Differential depends on last full
- SQL log backup sets either with or without truncation depend on previous log backup sets plus the last full backup set
Backup chain dependents calculation with mixed incremental/differential sets is based on:
| Agent | Does an Incremental depend on last Differential since last Full? | Does a Differential depend on prior Incremental since last Full? | |
| Hyper-V/Virtual Server | No | No | |
| Oracle | Yes | No | |
| Unix/Mac | Yes | No | |
| NDMP filer | Yes | No | |
| Domino | Yes | Yes | |
| SQL | Yes | No | |
| SharePoint | Databases | No | No |
| Index Files | No | Yes | |
| Other agents: NTFS, System State, Shadow Copy, SQL, SharePoint, Exchange, VMware, Hyper-V, EV | No | Yes | |
This is one of four Dependency Rules.
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When Copy Exists Dependent Rule
An expired backup set (non-critical) does not have any dependents and can be deleted by DLM if:
It has at least one copy
For GRT-enabled sets:
- A copy must be on another DLM-managed storage device (non‑tape)
- A duplicate on tape based storage is not considered a copy
AND
It is not the last copy to expire
- It is not the copy with the farthest expiry date
- Copy could be original set OR set resulting from ‘duplicate stage’
Critical backup sets have additional dependencies that are described in the Simplified Disaster Recovery (SDR) Backup Sets Dependent Rule.
This is one of four Dependency Rules.
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Last Copy to Expire Dependent Rule
If an expired backup set (non-critical) has a copy and is the last copy to expire then:
| Expired backup set contains | Can be deleted if: |
| Non GRT-enabled sets | Its own dependents and dependents of its copies on all storage devices (including tape-based storages) expire |
| GRT-enabled sets | Its own dependents and dependents of its copies on all DLM-managed storage devices expire |
| Exchange backup sets (non-critical) from pre‑BE 2014 | Its dependents and copies on all storage devices (including tape-based storages) expire |
Critical backup sets have additional dependencies that are described in the Simplified Disaster Recovery (SDR) Backup Sets Dependent Rule.
This is one of four Dependency Rules.
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Simplified Disaster Recover (SDR) Backup Sets Dependent Rule
Simplified Disaster Recover (SDR) enabled Backup Sets have additional dependent backup sets corresponding to the sets of the Simplified System Protection (SSP) bundle needed for Simplified Disaster Recovery.
Backup sets of critical resources are considered an SSP bundle and are interdependent if:
- They were created as part of a single run of an SDR enabled backup job
- Have a valid (non-corrupt) System State backup set
For example:
- If an SDR job backed up critical volumes C: and E: along with System State (SS) as part of a Full backup
- Then C: Full, E: Full and SS Full backup set form an SSP bundle and are interdependent
This is one of three main DLM Retention Rules.
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DLM Rules and Dependencies Displayed in the Backup Exec Console
‘Expire’ and ‘Show Dependent backup Sets’ options display dependent sets based on DLM retention rules. These options display dependent sets from:
- Backup chain (Full/Incremental/Differential) related dependent sets
- Duplicate backup related sets
- For GRT-enabled duplicate copy related backup sets:
- A duplicate set on disk-based devices (disk, dedupe, RDX, cloud) will be considered as copy by DLM
- A duplicate set on tape will NOT be considered as copy by DLM
- Simplified System Protection (SSP) (Simplified Disaster Recovery (SDR) enabled backups) backup job related backup sets
The rules that define DLM dependents also determine the dependents that are displayed in the Backup Exec console. Which of the rules are applied and examples of the resulting dependencies are described for these scenarios:
- Dependents Displayed for NTFS and Other Non GRT-Enabled Sets
- Dependents Displayed for GRT-Enabled Sets
- Dependents Displayed for SDR Backup Sets on DLM-Managed Storage
- Dependents Displayed for SDR Backup Sets on Tape Storage
- Dependents Displayed for Pre-BE2014 Exchange GRT-Enabled Sets
Dependents Displayed for NTFS and Other Non GRT-Enabled Sets
Dependents Displayed for NTFS and Other Non GRT-Enabled Sets on DLM-Managed Storage
Both the ‘Expire’ and ‘Show Dependent backup Sets’ options display dependent sets on DLM-managed storage.
| If the selected backup set is a non‑critical set | Dependents Displayed |
DLM Rules Applied |
| Does NOT have any copy | As per backup chain | Backup Chain |
| Has at least one copy AND is NOT the last copy to expire | No dependents | When Copy Exists |
| Has at least one copy AND it is the last copy to expire | Dependents from its own backup chain + dependents of each of its copy | Backup Chain AND When Copy Exists |
Dependents displayed for critical sets are described as:
- Dependents Displayed for SDR Backup Sets on DLM-Managed Storage
- Dependents Displayed for SDR Backup Sets on Tape Storage
Dependents Displayed for Tape Storage
The ‘Show Dependent backup Sets’ option displays dependent sets on tape-based storage.
| If the selected backup set is a non‑critical set | Dependents Displayed |
DLM Rules Applied |
| Does NOT have any copy | As per backup chain | Backup Chain |
| Has at least one copy on another tape device | Dependents of its own backup chain + dependents of each of its copies on other tape devices | Backup Chain AND When Copy Exists |
| Has at least one copy on another non-tape device | Dependents of its own backup chain. It will not display dependents on non‑tape devices | Backup Chain AND When Copy Exists |
Example: NTFS Backup to Disk
If the Backup Chain includes: Full, Incremental 1, Incremental 2 and Full 1:
- Full will have Incremental 1 and Incremental 2 as dependents.
- Incremental 1 will have Incremental 2 as dependents.
- Incremental 2 will have no dependents.
Example: NTFS Backup to Disk and Duplicate to Dedupe
If the Backup Chain includes: Full, Incremental 1, Incremental 2 and Full 1:
| Selected backup set | Dependants On Disk (Original set) | Dependents On Dedupe (Duplicate set) |
| Full | No dependents | Incremental 1, Incremental 2 on Disk and Dedupe |
| Incremental 1 | No dependents | Incremental 2 on Disk and Dedupe |
| Incremental 2 | No dependents | No dependents |
Example: NTFS Backup to Disk and Duplicate to Tape
If the Backup Chain includes: Full, Incremental 1, Incremental 2 and Full 1:
Dependents on tape are displayed from the ‘Show Dependent Backup Set’ option
| Selected backup set | Dependants On Disk (Original set) | Dependents On Tape (Duplicate set) |
| Full | No dependents | Incremental 1, Incremental 2 on Tape |
| Incremental 1 | No dependents | Incremental 2 on Tape |
| Incremental 2 | No dependents | No dependents |
Dependents Displayed for GRT-Enabled Sets
The ‘Expire’ option displays dependent sets on DLM-managed storage.
Note: Tape-based duplicate sets will not be considered as copies in these rules
| If the selected backup set | Dependents Displayed |
DLM Rules Applied |
| Does NOT have any copy | As per backup chain | Backup Chain |
| Has at least one copy AND it is NOT the last copy to expire | No dependents | When Copy Exists |
| Has at least one copy AND it is the last copy to expire | Dependents from its own backup chain + dependents of each of its copy | Backup Chain AND When Copy Exists |
Example: Exchange Backup To Disk and Duplicate to Tape
If the Backup Chain includes: Full, Incremental 1, Incremental 2 and Full 1:
Dependents on tape are displayed from the ‘Show Dependent Backup Set’ option
| Selected backup set | Dependants On Disk (Original set) |
Dependents On Tape (Duplicate set) |
| Full | Incremental 1, Incremental 2 on Disk (Tape is not considered as a copy) | Incremental 1, Incremental 2 on Tape |
| Incremental 1 | Incremental 2 on Disk | Incremental 2 on Tape |
| Incremental 2 | No dependents | No dependents |
Dependents displayed for tape-based GRT-enabled sets is the same as those displayed for NTFS sets Dependents Displayed for NTFS and Other Non GRT-Enabled Sets.
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Dependents Displayed for SDR Backup Sets on DLM-Managed Storage
Both the ‘Expire’ and ‘Show Dependent backup Sets’ options display dependent sets on DLM-managed storage.
| If the selected backup set is SDR | Dependents Displayed | DLM Rules Applied |
| Does NOT have any copy (also applies to Tape storage) | Include sets in SSP bundle + Incremental/Differential dependents of each of the sets in SSP bundle | Backup Chain AND SDR Backup Sets |
| Has at least one copy AND it is the last copy to expire | Include sets in SSP bundle + Incremental/Differential dependents of each of the sets in SSP bundle + Incremental/Differential dependents of all the copies of each of the sets in SSP bundle | Backup Chain AND When Copy Exists AND SDR Backup Sets |
| Is Critical volume such as C:, D:, has at least one copy AND it is NOT the last copy to expire | Include System State set of its SSP bundle | When Copy Exists AND SDR Backup Sets |
| Is System State, has at least one copy AND it is NOT the last copy to expire | No dependents | When Copy Exists AND SDR Backup Sets |
Example: SSP Backup to Disk
If the Backup Chain includes: Full, Incremental 1, Incremental 2 and Full 1 of C: and System State (SS):
- C: Full will have dependent sets: SS Full, C: Incremental 1, SS Incremental 1, C: Incremental 2, SS Incremental 2
- C: Incremental 1 will have dependent sets: SS Incremental 1, C: Incremental 2, SS Incremental 2
- C: Incremental 2 will have dependent sets: SS Incremental 2
- SS Full will have dependent sets: C: Full, C: Incremental 1, SS Incremental 1, C: Incremental 2, SS Incremental 2
- SS Incremental 1 will have dependent sets: C: Incremental 1, C: Incremental 2, SS Incremental 2
- SS Incremental 2 will have dependent sets: C: Incremental 2
Example: SSP Backup to Disk and Duplicate to Dedupe
If the Backup Chain includes: Full, Incremental 1, Incremental 2 and Full 1 of C:, E: and System State (SS):
| Selected backup set | Dependants On Disk (Original set) | Dependents On Dedupe (Duplicate set) |
|---|---|---|
| C: Full | SS Full on Disk | E:, SS Full on Dedupe; C:, E:, SS Incremental 1 on Dedupe, C:, E:, SS Incremental 2 on Dedupe; C:, E:, SS Incremental 1 on Disk; C:, E:, SS Incremental 2 on Disk |
| E: Full | SS Full on Disk | C:, SS Full on Dedupe; C:, E:, SS Incremental 1 on Dedupe, C:, E:, SS Incremental 2 on Dedupe; C:, E:, SS Incremental 1 on Disk; C:, E:, SS Incremental 2 on Disk |
| SS Full | No dependents | C:, E: Full on Dedupe; C:, E:, SS Incremental 1 on Dedupe, C:, E:, SS Incremental 2 on Dedupe; C:, E:, SS Incremental 1 on Disk; C:, E:, SS Incremental 2 on Disk |
| C: Incremental 1 | SS Incremental 1 on Disk | E:, SS Incremental 1 on Dedupe; C:, E:, SS Incremental 2 on Dedupe; C:, E:, SS Incremental 2 on Disk |
| E: Incremental 1 | SS Incremental 1 on Disk | C:,SS Incremental 1 on Dedupe; C:, E:, SS Incremental 2 on Dedupe; C:, E:, SS Incremental 2 on Disk |
| SS Incremental 1 | No dependents | C:, E: Incremental 1 on Dedupe; C:, E:, SS Incremental 2 on Dedupe; C:, E:, SS Incremental 2 on Disk |
| C: Incremental 2 | SS Incremental 2 on Disk | E:, SS Incremental 2 on Dedupe |
| E: Incremental 2 | SS Incremental 2 on Disk | C:, SS Incremental 2 on Dedupe |
| SS Incremental 2 | No dependents | C:, E: Incremental 2 on Dedupe |
Dependents Displayed for SDR Backup Sets on Tape Storage
The ‘Show Dependent backup Sets’ option displays dependent sets on tape-based storage.
| If the selected backup set is SDR | Dependents Displayed |
DLM Rules Applied |
|---|---|---|
| Has at least one copy on another tape device AND it is the last copy to expire | Include sets in SSP bundle + Incremental/Differential dependents of each of the sets in SSP bundle + Incremental/Differential dependents of all the copies of each of the sets in SSP bundle on tape storage | Backup Chain AND When Copy Exists AND SDR Backup Sets |
| Is Critical volume such as C:, D:, has at least one copy on another tape device AND it is NOT the last copy to expire | System State set of its SSP bundle as dependent + Incremental/Differential Dependents of its own backup chain + Incremental/Differential Dependents of each of its copies on other tape devices | Backup Chain AND When Copy Exists AND SDR Backup Sets |
| Is System state, has at least one copy on another tape device AND If it is NOT the last copy to expire | Incremental/Differential Dependents of its own backup chain + Incremental/Differential dependents of each of its copies on other tape devices as dependents | Backup Chain AND When Copy Exists AND SDR Backup Sets |
| Has at least one copy on another non-tape device AND it is the last copy to expire | Include sets in SSP bundle + Incremental/Differential dependents of each of the sets in SSP bundle + Incremental/Differential dependents of all the copies (tape/non-tape) of each of the sets in SSP bundle | Backup Chain AND When Copy Exists AND SDR Backup Sets |
| Is Critical volume such as C:, D:, has at least one copy on another non-tape device AND it is NOT the last copy to expire | Include System State set of its SSP bundle + Incremental/Differential Dependents of its own backup chain | Backup Chain AND When Copy Exists AND SDR Backup Sets |
| Is System state, has at least one copy on another non-tape device AND If it is NOT the last copy to expire | Include Incremental/Differential Dependents of its own backup chain | Backup Chain AND When Copy Exists AND SDR Backup Sets |
Dependents Displayed for Pre-BE2014 Exchange GRT-Enabled Sets
| If the selected backup set | Dependents Displayed |
Patch Applied |
| Is pre-BE2014 Exchange set AND has at least one copy on tape or non‑tape storage | Dependents from its own backup chain + all its copies + dependents of each of its copy on tape or non-tape storage | Registry change for Exchange backups included in BE2012 R2 and later |
Related Technical Articles
| Backup Exec Community Article | Automated Disk management and Data retention in Backup Exec (DLM or Data LifeCycle Management) |
Resolution
Data Lifecycle Management (DLM) Rules
DLM Retention Rules
DLM determines when a backup set expires according to the retention specified in the backup job. Expired backup set data, catalogs and database records will be deleted if DLM rules are met.
Storage devices DLM manages include:
- Disk storage, including deduplication storage
- Cloud storage
- Disk Cartridge Media (RDX storage)
Tape-based backup sets
- Are not managed by DLM
- Are overwritten per the media set retention policy
Backup sets may have passed their expiration time and are not being deleted by DLM due to one or more rules of DLM. There are three main rules of DLM that result in expired-but-not-deleted sets:Data Lifecycle Management (DLM) Backup Chain and Dependency Rules
- Set is part of Last Recovery Chain (Last Recovery Chain Rule)
- Set has one or more retained Dependents (Dependency Rules)
- Simplified Disaster Recover (SDR) enabled backup sets have additional Simplified System Protection (SSP) dependent sets (SDR Backup Sets Dependent Rule)
The Expire option:
- Is used for manual expiration of DLM-Managed backup sets
- Displays the list of dependents and allows users to expire all the dependent sets simultaneously
- Allows users to override Last Recovery Chain Rule
- If expired disk-based backup sets meet all DLM rules then the backup data and related catalogs and database entries will be deleted
The Retain option over-rides DLM. A backup set manually retained and all related dependencies will not be considered for deletion when DLM rules are applied.
The Show Dependent Backup Sets option displays dependents for both tape and DLM-managed backup sets.
Dependent backup sets are displayed in the Backup Exec console based on DLM Retention Rules (DLM Rules and Dependencies Displayed in the Backup Exec Console). Which of the rules are applied and examples of the resulting dependencies are described for these scenarios:
Issue/Introduction
Data Lifecycle Management (DLM) Backup Chain and Dependency Rules
