topic disk allocation in ONTAP Discussions

disk allocation

RATNATHURAI — Thu, 05 Jun 2025 05:59:44 GMT

I have a FAS2040 with dual controller and have two disk shelf.

one with 800GB and other 2.2TB, both are full shelf.

Can someone recomend me please a best disk assigment in which I will not mix the disks.

I need DP and spare disk too.

I thought of RG=20, this case I will have (18 data+1 paroty +1DP)+spare, but I will left with 4 *800GB disks and they are going to go to next RG: then I have to change the RG for 2.2TB. Is it the way to go?

Re: disk allocation

radek_kubka — Tue, 25 Jun 2013 12:08:50 GMT

Hi,

What ONTAP version are you on & what "marketed" disk capacities are you talking about - 1TB SATA & 3TB SATA by any chance?

Your likely layout should be RG size 11, so you have 2 RAID groups for each disk type plus two spares.

Regards,
Radek

Re: disk allocation

RATNATHURAI — Tue, 25 Jun 2013 13:11:42 GMT

800GB SATA and 2.2TB SATA.

Need max space.

Re: disk allocation

paul_wolf — Tue, 25 Jun 2013 13:16:21 GMT

Is this a different version of this question?

https://communities.netapp.com/thread/30257

I would recommend setting the RAID group size for SATA to 20 and for SAS/FC to 22. 20 is the maximum for SATA and 22 for SAS/FC gives you the best shelf usage/capcity numbers for DS-4243 disk shelves.

But that's just me.

Re: disk allocation

RATNATHURAI — Tue, 25 Jun 2013 13:28:55 GMT

Paul,

Can I mix small disk (800GBSATA) into larger disk group.?

Here I have two diks capacities.

If I start the aggregate with 2.2TB then I will have few spare disks becuase FAS2040 has aggregate size limit to 30TB?

I have go go for next aggregate and I have to start with 2.2TB , then 800GB.

Re: disk allocation

paul_wolf — Tue, 25 Jun 2013 13:42:50 GMT

Sorry, I forgot about that this is a 2040 but a 20 disk RAID group with 2TB SATA is 26.19 TB usable and is valid for a 2040 running ONTAP 8.

I'm not sure what you mean when you say 2.2 TB SATA as I don't recall that NetApp has drives of that size.

And 800GB is not SATA, it's SAS so those drive types should never be mixed in the same RAID group as the 2TB SATA will be configured as if they were 800GB as the RAID group disk size will be the size of the smallest disk in the RAID group. You can mix disk types the same aggregate but I would not recommend it. Instead create one aggregate from the SATA disk drives and one aggregate from the SAS disk drives.

Re: disk allocation

radek_kubka — Tue, 25 Jun 2013 14:08:04 GMT

I'm not sure what you mean when you say 2.2 TB SATA as I don't recall that NetApp has drives of that size.

I reckon this is how 3TB drives present themselves in real life

And 800GB is not SATA, it's SAS

These are quite likely 1TB SATA drives (right-sized to 847GB)