Some questions about SA P824i-p MR Gen10 Controller

[MSoft]

Hello everyone,

I'm installing a new DL380 Gen10 server (Windows Server 2019) and having some questions related to the P824-i controller. Questions summed below.

I've created a RAID10 array on 16 1.2TB HDDs. In the logical drive creation process, it asked me to manually create spans (min 2) and select drives for each of them. The documentation provides no help and searches on the internet lead to even more confusion for what is actually a span in a RAID10 and how should I choose the drives. I've created 2 spans with 8 drives each, which resulted in 8.73TiB.
Additionally the controller does not support encyprtion for data in rest. I'm thinking of buying a TPM module and using BitLocker with TPM+PIN. Is this a viable option? Are there better ones?

Questions summary:
1. What is a span in (MegaRAID's) RAID10 and how is the data actually stored on the drives?
2. Is 2 spans with 8 drives each the optimal configuration for 16 drives, or I had to choose 8 spans with 2 drives each? In 2 spans/8 drives configuration, is the point of failure still the 9th drive (theoretically/unreally lucky)?
3. How to encypt the data in rest? Is BitLocker the best option?

Thanks in advance.

[BPSingh]

Disk spanning allows multiple drives to function like one big drive.

RAID 10, a combination of RAID 0 and RAID 1, consists of striped data across mirrored spans. A RAID 10 drive group is a spanned drive group that creates a striped set from a series of mirrored drives. RAID 10 allows a maximum of eight spans. You must use an even number of drives in each RAID virtual drive in the span. The RAID 1 virtual drives must have the same stripe size.

https://support.hpe.com/hpsc/doc/public/display?docId=a00048286en_us

Unlike other HPE Smart Array SR Gen10 Controllers, HPE Smart Array P824i-p MR Gen10 Controller does not support HPE Smart Array SR Secure Encryption. Hence Bitlocker can be used as you have mentioned.