I don't know if the "failfast" patch was ever pushed into the kernel back in 2017, but if it was, does it change anything in regards to the SCTERC/Kernel-driver. timeout issue(s)? Link to a thread about the patch: https://lkml.org/lkml/2016/11/18/1 And what is the reason why mdadm just doesn't mark a drive fail if no response has been received from a array-member-device within e.g. 29 seconds (just less than kernel-driver default timeout of 30 sec) e.g. because of write/read issue. Then all those SCTERC/kernel-driver timeout-issues would be solved, right?