Linux RAID Performance On Dual NVMe SSDs

To no real surprise by now, Btrfs out-of-the-box is slowest at the SQLite test of the four tested mainline file-systems. One could disable the CoW functionality of Btrfs, but then you lose out on Btrfs' desirable features. F2FS was performing in line with XFS as the fastest on these tests. What is interesting to note is the apparent regression with EXT4 in MD RAID1 with its performance slowing down about 3x.

With sequential reads in FIO, EXT4 differentiated itself from the competition with a much greater lead in RAID0 performance compared to its tight performance when testing the FS performance standalone on one Samsung 960 EVO drive. Also notable is that F2FS on MD RAID in this test didn't end up being any faster, unlike the three other tested file-systems, but it did do better with RAID1.

The sequential write performance was much more clear and in line with expectations. EXT4 in RAID1 did see a significant performance drop of similar magnitude to the SQLite run.