RAID doesn’t checksum and heal the rotten data. It’s game over before you even have a filesystem on top of it, because said filesystem can’t directly access the underlying disks because of the RAID layer.
Errors will occur, and RAID has no way of handling it. You have a RAID1, disk 1 says it’s a 0, disk 2 says it’s a 1. Who’s right? RAID can’t tell, btrfs and ZFS can. RAID won’t even notice there’s a couple flipped bits, it’ll just pass them along. ZFS will just retry the read on both disks, pick the block that matches the checksum, and write the correct data back on the other disk. That’s why people with lots of data loves ZFS and RAIDZ.
The solution isn’t more reliable hardware, the solution software that can tell you and recover from your failing hardware.
RAID doesn’t checksum and heal the rotten data. It’s game over before you even have a filesystem on top of it, because said filesystem can’t directly access the underlying disks because of the RAID layer.
Errors will occur, and RAID has no way of handling it. You have a RAID1, disk 1 says it’s a 0, disk 2 says it’s a 1. Who’s right? RAID can’t tell, btrfs and ZFS can. RAID won’t even notice there’s a couple flipped bits, it’ll just pass them along. ZFS will just retry the read on both disks, pick the block that matches the checksum, and write the correct data back on the other disk. That’s why people with lots of data loves ZFS and RAIDZ.
The solution isn’t more reliable hardware, the solution software that can tell you and recover from your failing hardware.