topic Re: qtree quotas on deduplicated volumes in ONTAP Discussions

qtree quotas on deduplicated volumes

MSANDONASSGA — Thu, 05 Jun 2025 06:33:56 GMT

I'm trying to figure out what affect enabling deduplication on volume will have on qtrees with quotas.

Say I have a 1 TB VOL with multiple qtrees and quotas. QtreeX - quota 300 GB; 270 GB utilized - has a ton of duplicate data.

After enabling and completing a dedupe pass, VOL utilization is reduced by 20%. 50 GB of the space savings was in QtreeX.

Will the quota utilization report now report 220 GB utilized or will it still report 270 GB used.

I found the following in the deduplication FAQ pdf. I'm assuming from this that the quota report will still indicate qtree utilization as 270 GB and will not be impacted by the reduced VOL utilization but I'm not entirely sure that that is what this is telling me:

Thank you.

Matt

26. ONCE A VOLUME IS DEDUPLICATED, HOW ARE QUOTAS REPORTED?

Quotas measure the apparent (logical) usage in the active file system and are unaware of any underlying block sharing. Therefore quota reporting is not affected by deduplication.

Re: qtree quotas on deduplicated volumes

pascalduk — Thu, 23 Feb 2012 06:31:50 GMT

Quota will indeed be reported as if the data is not deduplicated. In your example 270 GB will still be returned.

Same happens if you would use Data ONTAP compression.

Re: qtree quotas on deduplicated volumes

MSANDONASSGA — Thu, 23 Feb 2012 12:51:35 GMT

Thank you, Pascal.

Re: qtree quotas on deduplicated volumes

babar — Sun, 09 Mar 2014 05:47:04 GMT

Hi Pascal,

I dont think its the case for compression. https://library.netapp.com/ecmdocs/ECMP1196890/html/man1/na_quota.1.html mentions that "

Quotas do count space saved by compression. In a volume that has compressed

data, quotas count the sum of allocated used space and spaced saved by

compression."

Re: qtree quotas on deduplicated volumes

lhoffman1 — Wed, 19 Mar 2014 08:15:37 GMT

@babar:

quotas count the sum of allocated used space and spaced saved by compression

means related to the example above: 270GB anyway !