I was recently forced to move from an Areca RAID controller to the on-board solution based on AMD's B550 chipset. The problem I am encountering is that the RAID performance is very poor: I am trying to initialize a simple RAID1 array consisting of two 18 TB harddisks, and after 130 hours I am at 42 %. That translates to something like 16 MB/s (or 32 MB/s of a total throughput). In comparison, when I had to rebuild a 6x18 TB RAID6 array on my 12-year-old Areca card, it only took 78 hours. I understand that the Areca card had a dedicated chip for performing the calculations, but still - it's a fairly simple chip from before 2010 and I did not expect that it would perform so much better than a fairly recent system with an 8-core Ryzen 5700 CPU, especially considering that RAID1's calculations are so much simpler than RAID6's. Am I doing something wrong or is this kind of performance expected? I am worried what would happen if one drive died on me and had to be replaced - I really don't want to see 3+ week rebuild times!
