Data Domain: How to delete data outside the backup application

Summary: This document explains the role of a Data Domain in the handling of backup data, and possible ways to delete existing data already in the DD, should the need arise.

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Instructions

What is the role of the Data Domain in the backup environment?
The backup application is responsible for writing data to the Data Domain during a backup; reading data from the Data Domain as part of a recovery; maintaining a catalog or database of this data; determining when data has reached its retention period and expiring/deleting data.

The Data Domain is considered a passive device in that it does not control retention of the data and it does not expire any data. It only deletes files when commanded by one of its protocols (that is CIFS/NFS/DDBOOST.)  
 
If data is being managed by a backup application:    
If the data to be deleted is managed by a backup application, then the data should be expired/deleted through the backup application to preserve the integrity of the backup application catalog/database. Reach out to the backup application vendor for instructions on how to safely expire/delete data through the backup application.
 
If data is not being managed by a backup application or has become orphaned:    
If the data to be deleted is not being managed by a backup application, then it can be deleted manually from the Data Domain. This can be done with the following steps:   
  1. Create a snapshot to roll back any deletions if there is mistakes:    
  • Create a snapshot for the mtrees which will have data deleted with an expiry time of 1 week. This allows recovery if there is mistakes, within this time period.
  • For example, if only the mtree /data/col1/foo is impacted, the following command can be used:     
# snapshot create snap-deletions mtree /data/col1/foo retention 1week
  1. Accessing data using CIFS or NFS:    
  • NOTE: Instructions on how to manually delete VTL tapes can be found in the section below "Deleting VTL tapes."
  • Data can be deleted manually through CIFs or NFS. Use the instructions in the below KB articles (see below links) as a guide to create a CIFs/NFS mount to the specific mtree for which the deletions will be performed.
  • Dell EMC Data Domain Boost data should not be deleted through a CIFs share as it can cause permission issues for the remaining backup images. If Dell EMC Data Domain Boost data must be deleted and a backup application no longer manages it NFS must be used to delete the data.
    Access the CIFs share or NFS mounts through your client workstation. Instructions on how to do this are in these Knowledge Articles:
    Data Domain: Configuring a CIFS Share 
    Data Domain: Mounting and Verifying Exports on the NFS Client
       
  1. Removing data using CIFS or NFS
    • Important: Do not delete ddboost data using CIFS as it causes permissions issues with other backups. Use NFS instead.
    • If deleting with CIFS,
      • You can select the files in Windows Explorer and remove by right clicking and selecting Delete or by using the del  command in a Windows Command Prompt.
    • If using an NFS mount, the Linux/UNIX command rm  can be used.
    • With Linux and NFS, you can use the find command to look for files to remove
      • You would first cd into the mount point for the nfs export
      • For example, if you wanted to delete all files older than 30 days, you would use this command: 
        • find ./ -type f -mtime +30 -delete
        • -type f looks for files instead of dirs
        • -mtime is a number of days
        • -delete will remove any files that are found
      • Another example if you want to exclude certain directories from the search: 
        • find ./ -not \( -path ./SQL_Backups -prune \)  -not \( -path ./PSQL_backups -prune \) -name *logs* -delete
        • This prevents find from searching in dirs SQL_Backups and PSQL_backups
        • You can exclude as many dirs as you want using this syntax
        • -name in this example is searching for any files that have the word "logs" in the filename
  2. Expire the snapshot:   
  • Once data has been deleted and it is confirmed that none of the deleted files need to be restored, the snapshot created in step 1 can be expired with the command:     
# snapshot expire snap-deletions mtree /data/col1/foo
  • If this snapshot is not expired here, it remains on the system until its expiry time and may prevent space from being freed by cleaning.
  1. Start Cleaning:    
  • Once deletions are complete and the snapshot is expired, cleaning can be manually started with the command:     
# filesys clean start
  •        More options for running cleaning, such as changing the cleaning throttle, can be found in the following KB:    

Deleting VTL tapes:    
  • VTL tapes should always be managed through a backup application as there is no way for the Data Domain to identify which tapes contain specific data.  
  • If the barcode of the tapes to be deleted is known, the following commands can be used to delete specific tapes:     
# vtl tape show {all | pool <pool> | vault | <vtl>}

# vtl tape del <barcode> [count <count>] [pool <pool>] 

Affected Products

Data Domain, Data Domain Deduplication Storage Systems

Products

Data Domain
Article Properties
Article Number: 000021274
Article Type: How To
Last Modified: 11 Nov 2025
Version:  5
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