topic Re: Don't waste resources in a HA 7-Mode in ONTAP Discussions

Don't waste resources in a HA 7-Mode

danos — Thu, 05 Jun 2025 05:21:08 GMT

Hi,

I have a FAS 2520 in 7-Mode with 12x900GB disk and two controllers. After system setup, I've realized that each controller has 6 disks (3 for aggr0 and 3 spare disks) and I can't create new aggregates because there aren't enough spare disk. As I can't create new aggregates with this configuration, I'm thinking to change 2 spare disks from the Controller B to the Controller A, and add 4 disk to aggr0 in Controller A, leaving just one spare disk to each aggregate. I don't know if this configuration can be done, and if it's so, would I have High Availability if the Controller A fails? because I don't know either if volumes of Contoller A could be reach from Controller B when Controller A fails.

Anyway, what do you think is a good configuration to have high availability and not wasting resources?

Thanks, best regards.

Re: Don't waste resources in a HA 7-Mode

JGPSHNTAP — Tue, 30 Dec 2014 14:22:28 GMT

First things first, why are we setting up a 2050 as a new controller. This is EOA, you should consider upgrading.

If you want to setup in HA mode, you need to do the following

Combine aggr0 with data on one node. and make the other node raid-4.

The problem is you don't have a lot of disks, so you can use one hot spare on each head...

The reality of it is, you need a newer controller and more disks.

Re: Don't waste resources in a HA 7-Mode

danos — Tue, 30 Dec 2014 21:41:10 GMT

Hello JGPSHNTAP,

Thanks for your answer.

It's a FAS2520, no 2025, sorry for the confusion.

I think I'm going to configure an aggregate with just a spare disk in each controller. I've been trying to use all disks, without spare disks but I don't know how to do that.

Thanks, best regards.

Re: Don't waste resources in a HA 7-Mode

JGPSHNTAP — Wed, 31 Dec 2014 13:49:32 GMT

i apologize, i read it to fast... 2520 sounds better..

So, if you want HA mode with 12 disks (which is hard)

You will run active/passive setup, (confusing b/c it's really active/active, but all your data will be on one head)

So, Controller A - 8 disks aggr0 1 spare

controller b - raid 4 aggr0 - 2 disks, one spare

There's your 12 disks...

This is a new controller so if you are having problems with setting that up, just give support a call

Re: Don't waste resources in a HA 7-Mode

danos — Wed, 31 Dec 2014 14:42:21 GMT

Hi JGPSHNTAP,

That sounds good, thanks for your recomendation.

Merry Christmas, best regards.