Viewing storage usage within deduplication container files

Article:TECH195301  |  Created: 2012-08-21  |  Updated: 2013-01-04  |  Article URL http://www.symantec.com/docs/TECH195301
Article Type
Technical Solution


Issue



Viewing storage usage within deduplication container files.


Solution



A deduplication command reports on storage usage within containers.

The following is the pathname of the command:

  • On Windows systems, the path name of the command is install_path\Backup Exec>crcontrol.exe --dsstat  

The following is an example of the command usage on a Windows deduplication storage server. The command shows the data store statistics (--dsstat option).

C:\Program Files\Backup Exec>crcontrol.exe --dsstat

  ************ Data Store statistics ************
Data storage       Size   Used  Avail Use%
                  35.1T   5.3T  29.8T  15%
Number of containers             : 98125
Average container size           : 268211087 bytes (255.79MB)
Space allocated for containers   : 26318212931722 bytes (23.94TB)
Space used within containers     : 24563636296449 bytes (22.34TB)
Space available within containers: 1754576635273 bytes (1.60TB)
Space needs compaction           : 18875042669860 bytes (17.17TB)
Records marked for compaction    : 139455139
Active records                   : 43562983
Total records                    : 183018122

The following is an example of the command usage. The command shows the data store statistics (--dsstat option).

Figure 'Container space usage' shown below is a visual representation of the deduplication storage space. From the crcontrol --dsstat output, you can determine the following:


  • The Size is obtained from the operating system, 35.1T in the preceding example output.

  • The Used space = the file system used space - Space available within containers - Space needs compaction. BackupExec obtains the file system used space from the operating system. For the preceding example output, the file system used space - 1.6TB - 17.17TB = 5.3TB.

    The space actually used to store data = Space used within containers - Space needs compaction: 22.34TB - 17.17TB = 5.17TB. This value differs from the 5.3TB in the example output because the command output includes the overhead space that is used in the data store.

  • The available space (Avail) = Size - Used, 35.1TB - 5.3TB = 29.8TB in this example.

  • The percentage of space used (Use%) = Used / Size, 5.3TB / 35.1TB = 15%.

For help with the command options, use the --help option.

The BackupExec Deduplication Manager periodically compacts the space available inside the container files. Therefore, space within a container is not available as soon as it is free. Various internal parameters control whether a container file is compacted. Although space may be available within a container file, the file may not be eligible for compaction. The BackupExec Deduplication Manager checks for space every 20 seconds.





Article URL http://www.symantec.com/docs/TECH195301


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