Re: FAS2552 Hybrid with additional disk shelf optimal aggregate structure

vlsunetapp · ‎2021-11-06

Hello, ONTAP gurus!

Help find the best layout for this equipment and load:

- original FAS2552 dual-controller DS2246 with 4x400GB SSDs and 20x1TB SAS - shelf 1.0

- later added additionsl disk shelf DS2246 with 24x1TB SAS drives - shelf 1.1.

Main goal is to get maximim storage flexibility and feature usage (Flash Pool) for small data center with following loads:

- user data access via CIFS/NFS

- small vitrual cluster with 2-4 Hyper-V nodes with SMB 3 data VM storage.

This is current ONTAP 9.8 configuration recommentation and system state when use System Manager/ONTAP auto-configuration:

SSDs 1.0.0-1.0.3 - untouched by recomendation and not used at all, but want to use Flash Cache for user data access;

HDDs 1.0.4-1.0.23 partitioned to store node1/2 root agregates and have raid group 0 for each node data aggregate.

HDDs 1.1.0-1.1.19 equally assigned to each node and have raid group 1 for each node data aggreagate.

Two aggregates auto created with two raid groups each for node 1 and node 2 - see picture

We have 4 unused SSDs and 4 HDDs reserved for spares (hm, why not 2?).

Each created data aggregate on node 1 and node 2 have two RAID groups rg0 (10 partitions on shelf 1.0)and rg1 (10 drives on shelf 1.1).

Auto-partition function says that in can not reccomend what to do with SSDs and have created total two new data aggregates (1 for each node).

My questions are:
1. Can we manually switch/recreate such configuration for aggregates without conflicting optimal ONTAP recommendations:
- create SSD pool using 4xSSDs;
- create for both nodes two different partitions for used data access and some cata center loads:
aggr_NodeA_01 - with SSD flash pool caching for user data access via CIFS/NFS - 10 partitions on shelf 1.0;
aggr_NodeA_02 - Hyper-V VM storage with SMB 3 access - 10 drives on shelf 1.1;
aggr_NodeB_01 - with SSD flash pool caching for user data access via CIFS/NFS - 10 pertitions on shelf 1.0
aggr_NodeB_02 - Hyper-V/SQL etc. storage for data center loads (NAS or SAN) - 10 drives on shelf 1.1.
2. Does configuration in (1) conflicts with optimal NetApp raid group values or creates some performance issues?
3. Because of 4 aggregates we now have some flexibility to turn on/off Flash Pool for aggregates on shelf 0 (we have to recreate aggregate to turn off Flash Pool, so its flexibility to move volumes) - isn't it?
4. Having experience with traditional RAID controllers, I want to know how data volume stored on default created aggregate which consists of two raid-dp groups rg0 (10 partitions) and rg1 (10 drives) - does volume on such aggregate use only one rg or both?
5. Are there any chances to use two more spares for data?

Thanks for any help!

Fabian1993 · ‎2021-11-07

Hi,

my suggestion would be that you use your internal Disk (20) which are using ADPv1 in one Aggregate, max RG Size is 24, you can set up the Aggregate with 18/19 Disk (if you leave 2 Spare Disk, you can use Disk Mainteance Center). From the Shelf I woud also create only one Aggregate with 22/23 Disk (if you leave 2 Spare Disk, you can use Disk Mainteance Center). Data_Aggr1_Owner-Node01 and Data_Aggr2_Owner-Node02, with that you have the best Capacity/Performace mix. With the 4xSSD you can set up Storage Pool with Allocation Units, than you are flexible.

vlsunetapp · ‎2021-11-07

Thank you, Fabian1993. That is good alternative to auto sugested by ONTAP.

Why do you think about best performance? Is that because we have one raid-group per aggregate? While we lose 4 drives for spares in both situations, I guess that main factor to select original or your configuration is performance. One more factor is how to manage potential eddition of 1 disk shelf in future?

Is there any idea about how ONTAP manages volumes on aggregates which are created using two raid groups: are volumes placed on one raid goup in aggregate or ONTAP uses both raid groups per volume?