topic Re: Thick provisoned LUNs inside thin provisoned volumes? in ONTAP Hardware

Thick provisoned LUNs inside thin provisoned volumes?

sedakill1 — Thu, 05 Jun 2025 05:48:26 GMT

Hello All!

I've took over a FAS6280 and I'm trying to get a better understanding on how space is calculated using the following structure.

The engineer before me create all of his LUNs leveraging thick provisioning and then he put them in a volume that's thin provisioned. Where I'm getting confused is if I look at the volume's utilization it's showing as your would expect, i.e., the LUNs full thick provisoned size; however, if I look at the actual aggr utilization it doesn't show this space as being accounted for? Why is this?

TIA!

MY second question is when you flip between thin vs thick provisioning is the space immediately returned?

Re: Thick provisoned LUNs inside thin provisoned volumes?

aborzenkov — Fri, 29 Nov 2013 04:01:17 GMT

Space reservations on this provisioned volumes are not honored by containing aggregate. So in your case you have logical space reservation (in a volume) but it is not backed up by physical (in aggregate).

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29 нояб. 2013 г., в 0:42, "John Luin" <xdl-communities@communities.netapp.com<mailto:xdl-communities@communities.netapp.com>> написал(а):

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Thick provisoned LUNs inside thin provisoned volumes?

created by John Luin<https://communities.netapp.com/people/sedakill1> in Products & Solutions - View the full discussion<https://communities.netapp.com/message/121549#121549>

Hello All!

I've took over a FAS6280 and I'm trying to get a better understanding on how space is calculated using the following structure.

TIA!

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Re: Thick provisoned LUNs inside thin provisoned volumes?

saranraj456 — Sat, 30 Nov 2013 11:04:08 GMT

Reclamation of space will be done slowly based on the removal of inode in background

Re: Thick provisoned LUNs inside thin provisoned volumes?

saranraj456 — Sat, 30 Nov 2013 11:05:01 GMT

depends on the usage /size of the volumes,

Re: Thick provisoned LUNs inside thin provisoned volumes?

radek_kubka — Mon, 02 Dec 2013 15:05:49 GMT

Yes, this is very confusing with thick LUNs inside thin volumes. Volume reservation set to "file" gives a more logical outcome - if (and only if) a LUN is thick provisioned, the space will be reserved both in the containing volume & in the aggregate.

From my experience flipping between thick & thin provisioning returns reserved space immediately (the space isn't really filled with any data or zeroes, just reserved)

Re: Thick provisoned LUNs inside thin provisoned volumes?

saranraj456 — Fri, 06 Dec 2013 03:09:10 GMT

i meant the reclamation process will be slow , when it is filled by data .

Saran