recommended RAID configuration for Dell R650 with 5 drives, 1 of 5 smaller than rest

[Marc0p0l080]

Hi. I hope I have the right board.

We are deploying 2 new Dell R650s and a NetApp A220 SAN with vCenter 8 and ESXi 8. For some reason both systems came with 5 local drives, 4 x 960 GB and 1 x 600 GB. We plan on using the SAN for our primary VM storage and have the local RAID storage on each ESXi system as secondary and tertiary backups storage. The RAID controllers are PERC H755.

I'm not sure why 1 of the drives of each system is smaller than the other 5. My question is, should I set the RAID level to 10 and use all 5 drives for both OS and local VM backup storage? Also how much storage space should I allocate to the OS?

Any help would be appreciated.

[e_espinel]

Hello.
Let's deduce several things, since the info about the server is not detailed.
If you have 5 disks (4 of 906GB and 1 of 600GB) your front storage can be the 8X2.5". (8 disks wide 2.5").
The disks can be SAS/SATA or NVMe, but for their capacities we suppose that they are SSD SATA (960GB) and SAS (600GB).
You should verify that the PERC H755 controller has the RAID capacities you need such as RAID 0,1,10,5.
Considering this scenario and the task assigned for servers
a scheme would be
Option 1
SAS disk (600GB) operating system (ESXi) configured on RAID 0
4 Disks of 960GB for Data, configured in RAID 5 (about 75% of the total as usable space)
It should be considered that the operating system disk is not protected, if possible a second 600GB disk could be purchased to have a RAID1 for the operating system on each server.

Note: RAID configurations are created with disks of equal capacities and technology.

Option 2
On the first server place the two 600GB disks and 4 960GB disks to configure a RAID1 (600GB disks) for ESXi, and RAID5 (900GB disks) for Data.
On the second server place 4 disks (960GB) in RAID5 and create a volume (logical drive) of 200GB for ESXi and another volume (logic drive) with the rest of the available space for data.
Here we sacrifice a little disk space and a little speed for the ESXi.

https://kb.vmware.com/s/article/85685?lang=en_US&source=email