On Fri, 26 Jan 2024 00:30:46 -0300 Carlos Carvalho carlos@fisica.ufpr.br wrote:
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.
If Ext4 wouldn't work properly on parity RAID, then it is a bug that should be tracked down and fixed, not worked around by using a different FS. I am in disbelief you are seriously suggesting that, and to be honest really doubt there is any such high-profile "known" issue that stays unfixed and is just commonly worked around.