Reclaiming Data Domain Space

This article explains how to recover space on a Data Domain device from the command line manually. There is a weekly scheduled process to do this, but at times it is neccessary to run the process manually to free up space if prior to the scheduled task.

Note: You must be logged in as sysadmin on the data domain system to perform these tasks

  1. (optional) Check when last cleaning schedule took place:
    sysadmin@ddtst02# filesys clean status
    Cleaning finished at 2014/05/22 12:18:14.
  2. (optional) Check next cleaning schedule run
    sysadmin@ddtst02# filesys clean show config
            50 Percent Throttle
    Filesystem cleaning is scheduled to run "Mon" at "0600".
  3. (optional) Verify that we have space to reclaim
    sysadmin@ddtst02# filesys show space
    Active Tier:
    Resource           Size GiB   Used GiB    Avail GiB   Use%  Cleanable GiB*
    ----------------   --------   ---------   ---------   ----  -------------
    /data: pre-comp           -   1678028.9           -      -             -       
    /data: post-comp   165663.3    165663.3         0.0   100%       28605.6       
    /ddvar                 47.2        10.5        34.3    23%             -       
    /ddvar/core           984.3       368.6       565.7    38%             -
    ----------------   --------   ---------   ---------   ----  -------------
     * Estimated based on last cleaning of 2014/05/22 12:18:14.
    Note: The last column Cleanable GiB indicates the amount we could reclaim
  4. Manually start the cleaning process:
    sysadmin@ddtst02# filesys clean start nowait all
    Cleaning started. Use 'filesys clean watch' to monitor progress.
    The above command initiates the garbage collection process.
  5. We can watch the reclaiming status using the following command:
    sysadmin@ddtst02# filesys clean watch
    Beginning 'filesys clean' monitoring.  Use Control-C to stop monitoring.
    
    Cleaning: phase 1 of 12 (pre-merge)
         0% complete, 0 GiB free; time: phase  0:02:00, total  0:02:00
    
    Cleaning: phase 2 of 12 (pre-analysis)
         0% complete, 0 GiB free; time: phase  0:00:49, total  0:02:49
    
    Cleaning: phase 3 of 12 (pre-enumeration)
          0% complete, 0 GiB free; time: phase  0:00:52, total  0:03:42
            :
            :
    Cleaning: phase 11 of 12 (copy)
        100% complete, 28605 GiB free; time: phase  0:03:30, total  3:32:50
    
    Cleaning: phase 12 of 12 (summary)
        100% complete, 28605 GiB free; time: phase  0:02:26, total  3:35:16
    
  6. (optional) Confirm space has been reclaimed
    sysadmin@ddtst02# filesys show space
    Active Tier:
    Resource           Size GiB   Used GiB    Avail GiB   Use%  Cleanable GiB
    ----------------   --------   ---------   ---------   ----  -------------
    /data: pre-comp          -    1678028.9           -      -              -       
    /data: post-comp   165663.3    137057.7     28605.6    83%              -
    /ddvar                 47.2        10.5        34.3    23%              -       
    /ddvar/core           984.3       368.6       565.7    38%              -
    ----------------   --------   ---------   ---------   ----  -------------

Note: The data domain garbage collection isn't a fast process due the vast integrity checks also involved; A typical 10TB disk space reclaim could take up to around 4-5 hours to complete.

See my article Data domain cleaning phrases overview for a more detailed look at the cleaning phases involved.