> Read the wiki - the section on badblocks will be - enlightening - shall > we say. > > https://raid.wiki.kernel.org/index.php/The_Badblocks_controversy Yeah, I had read that already. Seems like a strange limbo state to be in with no clear way of fixing bad blocks.... Anyway, I think the bad blocks may be related to the problem I'm having now. At first everything looks good: bill@bill-desk:~$ cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] [linear] [multipath] [raid0] [raid1] [raid10] md0 : active raid5 sdk1[1] sdm1[4] sdj1[0] sdl1[2] 23441679360 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4] [UUUU] bitmap: 0/59 pages [0KB], 65536KB chunk unused devices: <none> bill@bill-desk:~$ sudo fsck /dev/md0 fsck from util-linux 2.34 e2fsck 1.45.3 (14-Jul-2019) /dev/md0: clean, 11274/366276608 files, 5285497435/5860419840 blocks bill@bill-desk:~$ sudo lsblk -f NAME FSTYPE LABEL UUID FSAVAIL FSUSE% MOUNTPOINT . . . sdj └─sdj1 linux_raid_member bill-desk:0 06ad8de5-3a7a-15ad-8811-6f44fcdee150 └─md0 ext4 ceef50e9-afdd-4903-899d-1ad05a0780e0 sdk └─sdk1 linux_raid_member bill-desk:0 06ad8de5-3a7a-15ad-8811-6f44fcdee150 └─md0 ext4 ceef50e9-afdd-4903-899d-1ad05a0780e0 sdl └─sdl1 linux_raid_member bill-desk:0 06ad8de5-3a7a-15ad-8811-6f44fcdee150 └─md0 ext4 ceef50e9-afdd-4903-899d-1ad05a0780e0 sdm └─sdm1 linux_raid_member bill-desk:0 06ad8de5-3a7a-15ad-8811-6f44fcdee150 └─md0 ext4 ceef50e9-afdd-4903-899d-1ad05a0780e0 But then I get confused about the UUIDs. I'm trying to automount the array using fstab (no unusual settings in there, just defaults), but I'm not sure which of the two UUIDs above to use. So I look at mdadm for help: bill@bill-desk:~$ sudo mdadm --examine --scan ARRAY /dev/md/0 metadata=1.2 UUID=06ad8de5:3a7a15ad:88116f44:fcdee150 name=bill-desk:0 However, if I use this UUID starting with "06ad", then I get an error: bill@bill-desk:~$ sudo mount -all mount: /media/bill/STUFF: mount(2) system call failed: Structure needs cleaning. But I don't know how to clean it if fsck says it's OK. On the other hand, if I use the UUID above starting with "ceef", then it mounts and everything seems OK. Basically, I don't understand why lsblk lists two UUIDs for the array, and why mdadm gives the wrong one in terms of mounting. This is where I was confused before about the UUID changing. Any insight here? Cheers, Bill
