Data Lifecycle Management (DLM) Backup Chain and Dependency Rules

Data Lifecycle Management (DLM) Backup Chain and Dependency Rules

Article: 100032333
Last Published: 2016-04-22
Ratings: 0 3
Product(s): Backup Exec

Solution

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
 
  1. Set is part of Last Recovery Chain (Last Recovery Chain Rule)
  2. Set has one or more retained Dependents (Dependency Rules)
    1. Backup Chain Dependents Rule
    2. When Copy Exists Dependent Rule
    3. Last Copy to Expire Dependent Rule
    4. SDR Backup Sets Dependent Rule
  3. 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:  

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:  
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
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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:
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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 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

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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

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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

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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
 
Article 000068230 Best practices for Backup Exec 2014/15 data lifecycle management (DLM)
Article 000076201 How data lifecycle management (DLM) deletes expired backup sets on disk-based storage
Veritas Community Article Automated Disk management and Data retention in Backup Exec (DLM or Data LifeCycle Management)

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