ONTAP Discussions

Advanced Drive Partitioning and data aggregate

Piotr335

Hello guys,

 

we have FAS2554 with 48x 6Tb drives deployed with Advanced Drive Partitioning enabled. 24 drives per each controller

 

I want to create 2 data aggreagtes one per controller.

I know that I can create aggreagte from 12 normal drives (5.35Tb) and then add the drives from data partition ( 5.3Tb) but they would need to be in different raid group and we will loose additional 3 drives ( raid tec)

 

Is there any option to create that data aggregate and have all drives in one raid group to not loose additional drives for next parity?

 

 

1 ACCEPTED SOLUTION

AlexDawson

For drives with a 6TB or larger marketing capacity, maximum RAID-DP raidgroup size is 14, so with 24 disks, you need to go to 2 raidgroups.

 

Fortunately, with ONTAP 9.1 and later, you can use RAID-TEC, with triple parity.

 

My suggestion would be to upgrade to 9.1, then use the internal ADP drives to create a single aggregate with a single RAID-TEC raidgroup of 23 disks (with 1 spare, or 24 without) for ~95TB usable, and then on the other controller, use the external drives in the same sort of configuration - single aggr single RAID-TEC raidgroup with ~96TB usable.

 

Hope this helps!

View solution in original post

4 REPLIES 4

AlexDawson

For drives with a 6TB or larger marketing capacity, maximum RAID-DP raidgroup size is 14, so with 24 disks, you need to go to 2 raidgroups.

 

Fortunately, with ONTAP 9.1 and later, you can use RAID-TEC, with triple parity.

 

My suggestion would be to upgrade to 9.1, then use the internal ADP drives to create a single aggregate with a single RAID-TEC raidgroup of 23 disks (with 1 spare, or 24 without) for ~95TB usable, and then on the other controller, use the external drives in the same sort of configuration - single aggr single RAID-TEC raidgroup with ~96TB usable.

 

Hope this helps!

View solution in original post

maxwellsdemon

@AlexDawson wrote:

My suggestion would be to upgrade to 9.1, then use the internal ADP drives to create a single aggregate with a single RAID-TEC raidgroup of 23 disks (with 1 spare, or 24 without) for ~95TB usable, and then on the other controller, use the external drives in the same sort of configuration - single aggr single RAID-TEC raidgroup with ~96TB usable.


Hi Alex

 

I think this is pretty much what I want to do with a freshly rebuilt FAS2240-4 on ONTAP 9.1 with 48 x 2.42TB Nearline drives.

 

All disks are the same. All odd number disks are owned by node 1, evens by node 2. We have root-data partitioning of the 24 disks in shelf 1, and the 24 disks in shelf 2 are unpartitioned spares. Both root aggregates are apparently 95% full with 180/189 GB used, and they each have 2 spare slices of 27.72 GB.

 

It seems from reading http://docs.netapp.com/ontap-9/topic/com.netapp.doc.dot-cm-psmg/GUID-07302AD3-F820-48F7-BD27-68DB0C2C49B5.html

that I can reassign all the Data partitions of shelf-1 to node 1 (leaving the Container and Root partitions owned by alternating nodes) and reassign the Container partitions in shelf 2 to node 2. Then I'll be able to make the wide-striped 20+3P raid groups that you suggest, with the shelf 2 Data slightly bigger than shelf 1.

 

Questions

1. Have I read that correctly?

2. Is there any downside to having different nodes own the Container, Root and Data partitions of some disks?

3. Should I be worried about the 95% full root partitions? This is freshly built and automatically partitioned. Do they need to be expanded?

AlexDawson

Hi there!

 

Mostly correct, slightly off-track on one aspect, and our documentation doesn't help - container in this context refers to a whole disk in a system with partitioned disks. At the point that the disk is partitioned, the container doesn't really have an owner that matters - only the partitions inside it do.

 

Root partition has a pretty low IO rate, so not much contention, but I'd still suggest it might be better to have the same owner for both. But it will work either way. 

 

95% full for root aggr is not great - you can add more root partitions to it to expand size, try to keep it below 80%. 

 

Hope this helps!

Piotr335

Hello Alex,

 

thanks for your reply I will keep that in mind for future deployments.

 

Right now I couldn't destroy both aggregates at one time due to having some data on them. So I had to move volumes from one aggregate to another to be able to destroy one.

 

Actually  now I have created data aggreagte with ADP disk drives and then I extended that aggregate with external disks. I lost 50g from every external drive beacuse they have scaled to the ADP drives but with this configuration I can have RAID-TEC data aggregate with only one raid group (size 22 and 2 spares) and I am not losing 3 drives for next raid group parity

 

 

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