On 30/07/2019 03:20, Bob Liu wrote: > [...] >> + * broken >> + * RAID0-only: same as clean, but array is missing a member. >> + * It's useful because RAID0 mounted-arrays aren't stopped >> + * when a member is gone, so this state will at least alert >> + * the user that something is wrong. > > > Curious why only raid0 has this issue? > > Thanks, -Bob Hi Bob, I understand that all other levels have fault-tolerance logic, while raid0 is just a "bypass" driver that selects the correct underlying device to send the BIO and blindly sends it. It's known to be a performance-only /lightweight solution whereas the other levels aim to be reliable. I've quickly tested raid5 and rai10, and see messages like this on kernel log when removing a device (in raid5): [35.764975] md/raid:md0: Disk failure on nvme1n1, disabling device. md/raid:md0: Operation continuing on 1 devices. The message seen in raid10 is basically the same. As a (cheap) comparison of the complexity among levels, look that: <...>/linux-mainline/drivers/md# cat raid5* | wc -l 14191 <...>/linux-mainline/drivers/md# cat raid10* | wc -l 5135 <...>/linux-mainline/drivers/md# cat raid0* | wc -l 820 Cheers, Guilherme
