Hi, [Copying Gary because they don't seem to be subscribed to the list so I do not know if they see replies that are only on the list.]
On Mon, Sep 14, 2026 at 07:40:22AM +0200, Michel Verdier wrote: > On 2026-09-13, Gary Dale wrote: > > > I can't fsck the partition obviously since it doesn't have a file system - > > just the mdadm superblock, if zeroing it left anything. > > Did you try to erase/recreate the partition, with fdisk or another tool ? What would be the theory behind why that would fix anything? That's just going to be a small amount of writes to the MBR or the GPT at the start/end of the entire disk, not the area of the problem partition. >From what I understand the issue is that mdadm reads the part of the disk for this partition and gets an I/O error. Gary rebooted; I'm not sure if it still happens after the reboot. Gary said they did a SMART long self-test and it passed. That's encouraging, but I have had the SMART self-tests pass even while there were actually unreadable sectors on the drive. I don't know why that happened, but it did. I did suggest a read of the whole disk with "dd" which helps to rule out issues. If there is a repeatable bad sector or small number of bad sectors on the drive, but the number of bad sectors isn't growing, I have had success with using "hdparm" to force a write to the problem sector(s), which either fixes the problem or make the drive remap to a spare sector. I/O errors are of course not always hardware problems. If things are working after a reboot then the root cause might have been some software thing and we may never know what it was. Thanks, Andy -- https://bitfolk.com/ -- No-nonsense VPS hosting
