Hello, > I needed "mdadm -E" the components of the array, so the partitions > rather than the whole devices. e.g. /dev/sdb1, not /dev/sdb. Sorry, that should have occurred to me. Here's the output: https://paste.ubuntu.com/26319689/ Indeed, bad blocks are present on two devices. > You can remove the bad block by over-writing it. > dd if=/dev/zero of=/dev/md0 bs=4K seek=1598030208 count=1 > though that might corrupt some file containing the block. I have tried that just now, but before running mdadm -E above. dd appears to succeed when writing to the bad block, but after that, reading that block with dd fails again: "dd: error reading '/dev/md0': Input/output error" In dmesg, the following errors appear: [220444.068715] VFS: Dirty inode writeback failed for block device md0 (err=-5). [220445.850229] Buffer I/O error on dev md0, logical block 1598030208, async page read I have repeated the dd write-then-read experiment, with identical results. The filesystem is indeed ext4, but it's not of tremendous importance to me that all data is recovered, as the array contains backup data only. However, I would like to get the backup system back into operation, so I'd be very grateful for further hints how to get the array into a usable state. Thank you so much for your help so far! -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
