RAID Groups and Aggregates - Noob

[londonitsupport]

Hi peeps,

Im still trying to understand RAID groups and how many disks we can and should fit into one. We have a 2040 HA Pair.

We currently have a SATA Tray (DS14MK2) with 14 1TB Disks arranged in 1 aggregate. 11 Disks with 2 parity and one spare. The RAID group was set to 14 (before I started).

We have a new shelf , the same DS14MK2 that I see can be added in two ways. The Shelf is primarily going to be used for snapmirror volumes from a DR site.

1)Assign disks to one of the two controllers

-create new aggregate

2)Assign disks to one of the two controllers

-add disks to existing aggregate

My questions center around the fact that the existing aggregate is 32bit, it is well under the 16TB limt (usable of around 8TB) so Can I add these new disks to this aggregate based on the RAID group size of 14.

thinking just adding, I won't need a spare as there is already one in the 1st shelf.

can we add all disks of this new shelf?

Should we upgrade our aggregate first to 64Bit, then add the disks?

Any help much appreciated.....

[scottgelb]

Which version of ONTAP are you on?  If not 8.1 then you have to match the aggr type (32 or 64) to the source.  If 8.1, then you can mirror 32 to 64 though.  The default raid group size for sata is 14 but that can be increased to 20 (and a hidden option to go to 22 which was posted on another community discussion). 

At a minimum you will need two raid groups with 27 drives anyway, so you can choose a new aggregate or add to the existing aggregate (but need to be on 8.1 which can convert 32 to 64 when growing over 16TB).  If you are on 8.0 or lower, then you likely would just create a new aggregate since you can't convert 32 to 64 without 8.1... or possibly wait to add the drives until you upgrade to 8.1.