4 x SSD Btrfs/EXT4 RAID Tests On Linux 4.15

First up with the SQLite test it ended up exhibiting some regressing behavior for the four disk RAID 1/5/6 modes and two disk RAID1 with EXT4. On the initial run of the SQLite benchmark, it was taking many times longer to complete the benchmark than in the non-RAID configuration... Subsequent runs were much faster, even with this test profile automatically removing the SQLite file in-between test runs, etc. EXT4 in RAID0 wasn't as affected and with Btrfs RAID there wasn't any wild swings in the performance. The fastest for this simple SQLite benchmark was simply the lone EXT4 disk.

With FIO random reads, Btrfs and EXT4 were performing about the same when using just a single SSD, but EXT4 RAID ended up scaling much better than the native Btrfs RAID. EXT4 RAID 4 disk tests were all performing much better than Btrfs four disk RAID.

With random writes, EXT4 RAID scaled much better as well.

But when running sequential reads on Linux 4.15, the Btrfs RAID performance outpaced EXT4.

EXT4 meanwhile offered better sequential write performance.