topic Re: Usable size of SAS disks in ONTAP Hardware

Usable size of SAS disks

stephnane — Thu, 05 Jun 2025 07:05:22 GMT

Hi !

Itried to search this onformatin on the Netapp Site but Icant find it ...

Where is the document which explains what is the usable capacity of a disk (exemple : SAS 450GB) with data ontap (7.3.2)?

Tks a lot.

Stephane

Re: Usable size of SAS disks

maske — Mon, 15 Nov 2010 16:56:55 GMT

Hi,

I have two links that may help you:

http://now.netapp.com/NOW/public/knowledge/docs/ontap/rel732/pdfs/ontap/210-04499.pdf

Page 31 states: Usable Space:

This is the total amount of space that

is available to the aggregate for provisioning.

This is computed as

Usable space = Total space -

WAFL reserve -

Snap reserve

df displays this as the ’total’ space.

The other link I have is about general sizing:

http://now.netapp.com/NOW/knowledge/docs/ontap/rel733/html/v-series/ig_hit/intro5.htm

Re: Usable size of SAS disks

stephnane — Tue, 16 Nov 2010 09:02:30 GMT

Thanks, but it doesn't resolve my problem. Here is another way to explain it :

I want to buy one SAS 450Gb 1500RPM disk in order to add it to an aggregate (so it will be usable, it wont be used as spare or parity). How could I know what amount of space I will add with this disk ?

In a training course, they give me this information for FC/SCSI/ATA/SATA disks, I need this information for SAS 450Gb Disks :

Example : FC/SCSI : Disk size 75Gb, right-sized capacity : 68Gb

Re: Usable size of SAS disks

stephnane — Tue, 16 Nov 2010 09:28:02 GMT

I found the information in the storage management guide - page 29.

I made a mistake in my research, i used "usable size" but it was better to search "right-sized capacity". ... I'm french