Data Domain: Total available storage space /data: post-comp Size can decrease over time

Summary: Total available storage space /data: post-comp Size can decrease over time. This is usually expected behavior, as the indices grow over time.

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Symptoms



Over time, the /data: post-comp Size can decrease. A decrease may be even more evident on DDVE [VIrtual datadomain] because they typically do not have a huge amount of storage
space to begin with.

#filesys show space
Active Tier:
Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB*
----------------   --------   --------   ---------   ----   --------------
/data: pre-comp           -      956.0           -      -                -
/data: post-comp     7288.5        222.5      7066.0     3%              0.0
/ddvar                 49.2        1.8        44.9     4%                -
/ddvar/core           158.5        0.2       150.2     0%                -

Four months later:   

 #filesys show space 
Active Tier:
Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB*
----------------   --------   --------   ---------   ----   --------------
/data: pre-comp           -   280981.2           -      -                -
/data: post-comp     6537.7     5659.2       878.5    87%              0.0
/ddvar                 49.2        7.7        39.0    17%                -
/ddvar/core           158.5        0.2       150.2     0%                -
----------------   --------   --------   ---------   ----   --------------

Cause

This is an expected behavior due to the space needed, to expand the indices, in accordance with the Data Domain file system architecture.
In the event that the index growth seems excessive  (more than 10% decrease of /data: post-comp space), please open a Support Request for assistance.

Resolution

The index file can be shrinked/consolidated by a manual rebuild operation, however it will grow again, in the future, to the size it needs to handle all the data hosted on Data Domain.

Rebuilding the index file will require to shutdown the filesystem [downtime] and it can take between 30 min to 12 hours depending on the complexity and the amount data stored.

Affected Products

Data Domain

Products

Data Domain
Article Properties
Article Number: 000061739
Article Type: Solution
Last Modified: 18 Sept 2025
Version:  3
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