AW: [EXTERNAL] options for adding a shelf/disks to an AFF-A220

Alexander Griesser <[email protected]> Sat, 28 Aug 2021 08:53:46 +0000

Newsgroups	gmane.comp.hardware.netapp
Message-ID	<[email protected]>

We do usually partition the disks with ADPv2 and add one data partition from each disk to one aggregate in a new raid group.
You can manually partition the drives and force the mandatory root partition to be as small as possible (depending on the drive size).

Depending on the size of your SSDs, it might be posible to go even down further on the number 9344:

disk assign -disk 4.12.* -owner YOURNODE1
node run -node YOURNODE1
disk show # to find the disk number, 0d.12.* here in this example
priv set diag
disk partition -n 3 -i 3 -b 9344 0d.12.0
disk partition -n 3 -i 3 -b 9344 0d.12.1
...

This will cause the new drives to be partitioned with the smallest possible root partition and two equally big data partitions.
For 3.84TB SSDs, the layout looks like this then:

CLUSTER::*> disk partition show -partition 4.12.0.*
Usable Container Container
Partition Size Type Name Owner
------------------------- ------- ------------- ----------------- -----------------
4.12.0.P1 1.75TB spare Pool0 YOURNODE1
4.12.0.P2 1.75TB spare Pool0 YOURNODE1
4.12.0.P3 28.75MB spare Pool0 YOURNODE1
3 entries were displayed.

Then assign the partitions to your nodes:

disk partition assign 4.12.*.P1 -owner YOURNODE1 -force true
disk partition assign 4.12.*.P2 -owner YOURNODE2 -force true

Verify the correct assignment:

CLUSTER::*> disk show -fields data1-owner,data2-owner,root-owner
disk data1-owner data2-owner root-owner
------- ----------- ----------- ----------
4.12.0 YOURNODE1 YOURNODE2 -
4.12.1 YOURNODE1 YOURNODE2 -
4.12.2 YOURNODE1 YOURNODE2 -
4.12.3 YOURNODE1 YOURNODE2 -
4.12.4 YOURNODE1 YOURNODE2 -
4.12.5 YOURNODE1 YOURNODE2 -
4.12.6 YOURNODE1 YOURNODE2 -
4.12.7 YOURNODE1 YOURNODE2 -
4.12.8 YOURNODE1 YOURNODE2 -
4.12.9 YOURNODE1 YOURNODE2 -
4.12.10 YOURNODE1 YOURNODE2 -
4.12.11 YOURNODE1 YOURNODE2 -

You can then add those partitions to a new raid group with the same rg size to the existing aggregates and will gain maximum striping across the disks.

If you made an error, just unpartition the disk in the node shell:

node run -node YOURNODE1
priv set diag
disk unpartition 0d.12.0

Best,

Alexander Griesser
Head of Systems Operations

ANEXIA Internetdienstleistungs GmbH

E-Mail: [email protected]
Web: http://www.anexia-it.com

Anschrift Hauptsitz Klagenfurt: Feldkirchnerstraße 140, 9020 Klagenfurt
Geschäftsführer: Alexander Windbichler
Firmenbuch: FN 289918a | Gerichtsstand: Klagenfurt | UID-Nummer: AT U63216601

-----Ursprüngliche Nachricht-----
Von: Toasters <[email protected]> Im Auftrag von Rue, Randy
Gesendet: Freitag, 27. August 2021 19:35
An: Toasters <[email protected]>
Betreff: [EXTERNAL] options for adding a shelf/disks to an AFF-A220

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Hi All,

I've cabled up the second external shelf for our AFF-A220 and it sees the disks. Now I'm at a fork in the road.

We currently have two local data tiers made up of 24 disks each, one on each node.

Best practices at
https://docs.netapp.com/ontap-9/index.jsp?topic=%2Fcom.netapp.doc.dot-cm-psmg%2FGUID-EE30CDA9-095F-4DD1-9A29-BB9F0E55DB4F.html
say a disk group of SSDs should be from 20-28 SSDs each.

If I go to create a new local tier the default is to create two new tiers, one on each node. That would give me two disks groups of 12, below the best practice. How badly would performance suffer? Any other caveats? Reliability?

I could put them all on one disk group, and on one node? Bleah.

I could add half of them to each existing tier/disk group and exceed the best practice by eight SSDs. I believe I've seen discussions (get it?) claiming that top limit is flexible with SSDs, was it here? But when I add another shelf I'll have the same problem.

Seems like the clearest path forward for consistency and future expansions is to add two tiers with small disk groups. So, can anyone guess if I'll have a significant performance impact? Any other caveats?

Grateful for any guidance,

Randy in Seattle

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