Dell EMC Unity: How to reduce the difference between used and allocated space for a UFS64 based filesystem (Dell EMC Correctable)
Summary: When viewing a UFS64 filesystem or datastore in the GUI a difference of almost 50% can be seen between used and allocated space. This can become a problem if there are space constraints within the pool. ...
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Instructions
If you would like to reduce the amount of space the array pre-allocates for UFS64 filesystems please contact support quoting this KB.
There is a parameter relating to each UFS64 filesystem that can be tweaked by support to reduce the allocated space.
The change is not immediate, a check is run every 1.5 hours and if after 5 consecutive checks the array determines action is required the FS shrink will start. It will then take a few hours for that to complete.
The change is persistent across reboots but not code upgrades.
Additional Information
You may also notice that when you look at the pool properties > Usage > Storage Resources that there is a higher value again for resource consumption. This value will also include metadata, space consumed by snaps and uncommitted space. The uncommitted space relates to internal system operations such as an incomplete shrink where slices are not yet released to the pool.
Affected Products
Dell EMC Unity FamilyProducts
Dell Unity 300, Dell EMC Unity 300F, Dell EMC Unity 400, Dell EMC Unity 400F, Dell EMC Unity 500, Dell EMC Unity 500F, Dell EMC Unity 600, Dell EMC Unity 600F, Dell EMC Unity Family |Dell EMC Unity All Flash, Dell EMC Unity FamilyArticle Properties
Article Number: 000019176
Article Type: How To
Last Modified: 13 Jun 2025
Version: 3
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