Phoronix published a review on the Linux RAID Performance On NVMe M.2 SSDs
A quote from the article:
For boosting the I/O performance of the AMD EPYC 7601 Tyan server I decided to play around with a Linux RAID setup this weekend using two NVMe M.2 SSDs. This is our first time running some Linux RAID benchmarks of NVMe M.2 SSDs and for this comparison were tests of EXT4 and F2FS with MDADM soft RAID as well as with Btrfs using its built-in native RAID capabilities for some interesting weekend benchmarks.Linux RAID Performance On NVMe M.2 SSDs @ Phoronix