Data Domain: Information about DD space utilization alerts[1]


   Article Number:     530701                                   Article Version: 3     Article Type:    How To 




Data Domain






All Data Domain Restorers (DDRs) contain a pool/area of storage known as the 'active tier':              
  •                 This is the area of disk where newly ingested files/data resides and on most DDRs files remain here until expired/deleted by a client backup application             
  •                 On DDRs configured with Extended Retention (ER) or Long Term Retention (LTR) the data movement process may periodically run to migrate old files from the active tier to archive or cloud tiers             
  •                 The only way in which to reclaim space in the active tier which was used by deleted/migrated files is by running the garbage collection/clean process (GC)             
               Current utilisation of the active tier can be displayed via the 'filesys show space' or 'df' commands:           
               # df           
               Active Tier:           
               Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB*           
               ----------------   --------   --------   ---------   ----   --------------           
               /data: pre-comp           -    33098.9           -      -                -           
               /data: post-comp    65460.3      518.7     64941.6     1%              0.0           
               /ddvar                 29.5       19.7         8.3    70%                -           
               /ddvar/core            31.5        0.2        29.7     1%                -           
               ----------------   --------   --------   ---------   ----   --------------           
               Note that, if configured, details of archive/cloud tiers will be shown below the active tier.           
               DD Space Usage alerts information:              
  •                 Data Domain have an internal design in such a way that it will automatically generate an alert when the DD reaches 90%, and this alert configuration cannot be changed, like if you want to generate that alert on 95% not at 90%, this cannot be achieved. The DD will show you alert when the DD become 90% full.              
  •                 The active tier may start to run out of available space causing alerts/messages such as the following to be displayed:             
               EVT-SPACE-00004: Space usage in Data Collection has exceeded 90% threshold : This is the initial alert which arrives when the DD space is 90% consumed, at this moment no processes will be impacted.           
               EVT-SPACE-00004: Space usage in Data Collection has exceeded 95% threshold : This alert will trigger when the DD reached at 95%, the performance may get impacted like cleaning and other processes.           
               EVT-SPACE-00004: Space usage in Data Collection has exceeded 100% threshold : If the active tier becomes 100% full no new data will be able to be written to the DDR which may cause backups/replication to fail, in this scenario alerts/messages such as the following may be displayed:           
               CRITICAL: MSG-CM-00002: /../vpart:/vol1/col1/cp1/cset: Container set [container set ID] out of space           
  •                 In some circumstances the active tier becoming full may cause the Data Domain File System (DDFS) to become read only at which point existing files cannot be deleted             
               Utilization of the active tier must be carefully managed otherwise the above may occur.