topic How to free "Temporary Deduplication" space? in ONTAP Discussions

How to free "Temporary Deduplication" space?

zamo2k — Wed, 04 Jun 2025 09:59:22 GMT

Hello,

we have a 8-node FASxxxx cluster with ONTAP 9.7P5.

One thick-provisioned volume had snapshots and deduplication set up.

The command

volume show-footprint

shows a "Temporary Deduplication" quota which goes over the size planned for that volume. I thus disabled deduplication (which benefits where lower than this temporary quota) but "Temporary Deduplication" is still there...

I read that this temporary quota may get "trapped" into snapshots, so I waited until snapshots became newer than the date I removed deduplication... but still "Temporary Deduplication" is there wasting 1,4TB of space.

How can I delete this useless temporary quota?

Thank you in advance.

Re: How to free "Temporary Deduplication" space?

RossC — Mon, 04 Jul 2022 03:14:50 GMT

Hi @zamo2k

Actually, likely kicking off another deduplication process would have helped reduce that dedup change log (temporary deduplication space).

Have a review of https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Software/ONTAP_OS/How_does_the_deduplication_changelog_work and https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Systems/FAS_Systems/How_to_justify_volume_metadata_footprint_in_ONTAP_9%3F

Hope this helps.

Re: How to free "Temporary Deduplication" space?

zamo2k — Mon, 04 Jul 2022 12:48:02 GMT

Hello RossC,

thank you very much for your hint!
Starting from it I discovered that actually re-running dedup solves a known issue: https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Software/ONTAP_OS/Volume_efficiency_policy_cannot_be_modified_and_volume_cannot_be_promoted

Thank you again!

Regards