Raid group size and aggregate size & fas2040 7.3.4

[ssibenetapp]

Hello,

I have a FAS2040 with 16 1TB SATA disks with 1 aggregate with RAID-DP (13data disks+ 2 dp + 1 hot spare disk) with dataontap 7.3.4. Now, Aggregate raid size group is 16

No we have to add 2 additional 1 TB Sata disks, but I'm not sure if it is possible with this configuration.

I have read:

- Aggregate size can be up to 19 disks ( not sure data disks or data+parity disks), it is sure?

- With raid group size in some docs appears max size for 7.3.4 and  sata disks 16, but other docs seems appears 20 (https://communities.netapp.com/message/2676), but I'm not sure what is the correct answer...

If Max raid size group is 16, it is possilbe to make another raid group with 1 disks or reduce previous created raid group and add some disks to new raid group?

It is possible to add 2 additional SATA disks with this configuration ? How?

Thanks

[scottgelb]

With the 16TB max aggregate size with 7.3 you can have up to 23 total drives and 19 data drives in the aggregate which would require 2 raid groups...but if you are only adding 2 disks, you could increase the raidsize and have 15D+2P after... the concern would be performance when you stripe on the 2 new disks... statit or perfstat can help identify if you will need to run reallocate...

You can't remove drives from the raid group or aggregate without destroying the aggregate...so the only choice is to grow the existing raid group without destroying is to add a new raid group to the aggregate, or create a new aggregate.  I would lean toward growing the existing raid group and increase the raid size if only adding 2 disks...but be careful on disk utilization on those 2 disks and be prepared to run reallocate if needed.

[ssibenetapp]

First of all, Thanks for your answer

One question, our dataontap versions is 7.3.4, What is the max raid size group for data ontap 7.3.4? It is possible to have 1 RG with 15D+2P without destroy aggregate? If we nee a second Raid group, It is possible to create a second raid group with only 1 o 2 disks?

About reallocate, after to add disks we always make a reallocate to force ensure all data is correct

thanks

[scottgelb]

Default is 14. Max is 20. Newer ontap has an override option to 22. With raid_dp a minimum of 3 disks per rg

Sent from my iPhone 5

[ssibenetapp]

Sorry, I'm a little confused because in https://library.netapp.com/ecmdocs/ECMP1134325/html/GUID-AA1419CF-50AB-41FF-A73C-C401741C847C.html#GUID-AA1419CF-50AB-41FF-A73C-C401741C847C__GUID-AE1... appears this for 7.3.4, What is the real max size? 16 or 20

RAID group sizes

RAID-DP	ATA/BSAS/SATA: 14 FC/SAS: 16	ATA/BSAS/SATA: 16 FC/SAS: 28	3
RAID4	ATA/BSAS/SATA: 7 FC/SAS: 8	FAS250: 14 All other models using ATA/BSAS/SATA: 7 All other models using FC/SAS: 14	2
RAID0	8	14	1

Thanks