ONTAP Discussions

Advanced Drive Partitioning and data aggregate

Piotr335
7,571 Views

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
7,495 Views

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!

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4 REPLIES 4

AlexDawson
7,496 Views

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!

Piotr335
7,436 Views

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

 

 

maxwellsdemon
6,603 Views

@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
6,594 Views

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!

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