I have a machine running #btrfs RAID1 with two SATA SSDs.
If I were to replace one of them with an NVMe SSD, would that improve performance, or would it be bottlenecked by the remaining SATA SSD?
(I know mdraid has a write-mostly mode, but I don't want to use it because (1) no bitrot correction and (2) I'd rather live with a performance hit than take my chances with a fragile tower of storage layers.)
@argv_minus_one I think it depends on the speeds of the nvme vs SATA path. Most of the time Nvme is a faster protocol. Since btrfs is doing the check in RAM for the checksum, it should be the same or better?
@argv_minus_one Read speed will come from the fastest device but write speed will be limited by your slowest device..
I would suspect you are still bottlenecked by the SATA path.
You may not notice anyway, depending upon the write load.