Space Reclamation

The Space Reclamation page allows you to manage space reclamation activity on the DXi4700. You can start or stop space reclamation. You can also monitor the progress of space reclamation activity.

During space reclamation, the DXi4700 searches the blockpool for tags that are no longer referenced and then deletes the unneeded tags to free up space.

In addition, the DXi automatically compacts reclaimable space in the following ways:

• During data ingest, reclaimable space is compacted as needed to provide space for new, deduplicated data.
• If the DXi is not in Low Space state, compaction starts when used disk space reaches a high level and there is sufficient reclaimable space. Compaction stops when used disk space falls below the high threshold state. The reclaimed space can be used to store new deduplicated or non-deduplicated data.
• If the DXi is in Low Space state, compaction starts and continues to run until the DXi exits Low Space state. The reclaimed space can be used to store new deduplicated or non-deduplicated data.

Note: The current compaction status is displayed on the Home page (see Home Page ).

Caution: For correct system operation, space reclamation must be run at regular intervals (at least once a week). Quantum recommends creating a schedule to automatically run space reclamation (see Scheduling Space Reclamation). Because space reclamation can affect system performance, avoid running space reclamation during known backup periods.

The space reclamation process can include up to four stages (see Space Reclamation Status).

New or Normal Mode	To increase performance, when space reclamation is initiated on the Space Reclamation page or as a scheduled event, only Stage 2 (Calculating Deletion Candidates) and Stage 3 (Deleting New Candidates) are run.
Low Space or Legacy Mode	When disk capacity is low, space reclamation is automatically started to free up disk space. In this case, all four stages of space reclamation are run.

To access the Space Reclamation page, click the Utilities menu, and then click the Space Reclamation tab (see Figure 1).

The Space Reclamation page displays the following information about the current or most recent space reclamation activity:

Status	The status of space reclamation (see Space Reclamation Status).
Stage Progress	The progress of the current space reclamation stage.
Total Progress	The overall progress of space reclamation activity.
Start Time	The time space reclamation started.
End Time	The time space reclamation ended.
Reclaimable Space	The disk space that is occupied by outdated deduplicated data and which will be automatically reused if additional space for new deduplicated data is needed. Displays Pending when space reclamation is running. Note: Because the DXi can automatically use reclaimable space to store new deduplicated data, space reclamation statistics may be affected (appear lower) if ingest occurs at the same time as space reclamation.