topic Re: Aggregate physical used less than volume physical used in ONTAP Discussions

Aggregate physical used less than volume physical used

DONBARTON1 — Tue, 26 Nov 2024 18:14:33 GMT

Hello All,

I think I have just been looking at this too long and it is an easy answer, but I have an aggregate that has 5954GB physical used and a volume in that aggregate that has 7903GB physical used. How is the physical volume larger than the aggregate?

I have looked at all the efficiencies and they add up independently, I just can't make the math above work. If anyone can point me in the right direction to see how this is possible I would be very grateful.

I can provide more output if needed.

Thanks!

Re: Aggregate physical used less than volume physical used

akiendl — Fri, 29 Nov 2024 06:45:16 GMT

Pretty sure you have set thin provisioning on the volume.

Thin provisioning

This allows you to make the volume larger than the aggregate is physically.

ak.

Re: Aggregate physical used less than volume physical used

DONBARTON1 — Mon, 02 Dec 2024 12:58:00 GMT

Thank you for your reply. Perhaps that is it. What is throwing me off is this. If it was thin-provisioning the total volume used (7720GB) would still show in the aggr used, correct?

What I do see now is the volume efficiencies are saving me 2.08 TB and the effective total footprint is 5.77TB

I guess what I am seeing in the aggr used (5860GB) is the total footprint volume including efficiencies?

Follow up: Is this where we would really have to pay attention to volume efficiencies? Aggr shows that I have 2.56TB available but I can only find out why if I look at the volume show-footprint.

Aggr Size: 8420GB

Aggr Used: 5860GB

volume size: 8396GB

vol used: 7720GB

Footprint Data Reduction: 2.08TB <--volume show-footprint command

Effective Total Footprint: 5.77TB <---volume show-footprint command

Re: Aggregate physical used less than volume physical used

DONBARTON1 — Thu, 19 Dec 2024 18:28:00 GMT

Just want to follow up. I figured out what I was not seeing. It was aggregate level dedupe.

Aggr show was throwing me off because of the aggr size of 8420GB. Since the space is saved at the aggregate level and not the volume level the volume size used is actually reported as larger than the aggregate total size. This was confusing me.