topic Re: NetApp FAS2650 ONTAP 9 Aggregate Disk Space Usage in ONTAP Discussions

NetApp FAS2650 ONTAP 9 Aggregate Disk Space Usage

edlam2000 — Wed, 04 Jun 2025 14:00:30 GMT

I am starting this discussion because I need to calculate Volume Sizing to avoid aggregate running out of disk spaces leading to LUN being offline, however, I find that my 16 TB aggregate after Volume and LUN assignment, is using only 208 GB used spaces and lots of free spaces left !!!!!!!!!!!!!

My 16 TB Aggregate has 3 Volumes as below:-

1st Volume 14 TB with 1 x 13 TB LUN with Space Reservation
2nd Volume 1.1 TB with 1 x 1 TB LUN with Space Reservation
3rd Volume 1 GB used by root

I have the 1st Volume above with Storage Efficiency Dedup and Compression scheduled running at midnight that has shown saving over 200 GB of disk spaces.

The 1st Volume holds a 13 TB LUN which is a vmware vmdk disk.

When I check the 13 TB LUN from its vmware client GUI, the Capacity shows that 10 TB has been used and only 3 TB left.

However, from the NetApp GUI, it shows that the 13 TB LUN only has 2.5% used, therefore, how can that be possible even with Dedup and Compression turned on that has only saved 223.5 GB ????

All my Volumes will NOT be using any snapshot, backup technology, snapmirror...etc that creates snapshot, however, I am using Storage Efficiency Dedup and Compression scheduled running at midnight, would it lead to temporary snapshot being generated in the process and I need to reserve spaces for snapshot ????????

Thanks for any advise !!!!!!

Re: NetApp FAS2650 ONTAP 9 Aggregate Disk Space Usage

GidonMarcus — Wed, 21 Feb 2018 12:10:20 GMT

What is your datastore full with????????? is it maybe VMDK's that full with 00000000000 ???

Re: NetApp FAS2650 ONTAP 9 Aggregate Disk Space Usage

edlam2000 — Thu, 22 Feb 2018 02:21:09 GMT

Thanks Marcus, you are right and you remind me of the vmware eager zeroed disk, and that's probably the reason.

I have just installed the VM with OS and that's probably the used spaces for the OS since there's no user data yet.

Do you know that if I don't use any snapshot, snapmirror..etc, that could result in snapshot, do I need to reserve extra spaces in the Volume for the scheduled Dedup and Compression???

I read that sometimes Dedup and Compression can produce temporary snapshot that taking up spaces in the process, and I am worrying about aggregate running out of disk spaces making the LUN offline.