Dan Moulding (dan@danm.net) wrote on Thu, Jan 25, 2024 at 05:31:30PM -03:
I then created an ext4 file system on the "data" volume, mounted it, and used "dd" to copy 1MiB blocks from /dev/urandom to a file on the "data" file system, and just let it run. Eventually "dd" hangs and top shows that md0_raid5 is using 100% CPU.
It's known that ext4 has these symptoms with parity raid. To make sure it's a raid problem you should try another filesystem or remount it with stripe=0.