# Re: clearing blocks wrongfully marked as bad if --update=no-bbl can't be used?

- From: Marc MERLIN \<hidden\>
- Date: 2016-10-30 17:16:54 
- List: linux-raid
- Page: https://ratatoskr.run/linux-raid/2016/10/6633249
- Thread: https://ratatoskr.run/linux-raid/2016/10/6633249/t.md

```text
On Sun, Oct 30, 2016 at 10:12:34AM -0700, Marc MERLIN wrote:
> Hi Neil,
> 
> Could you offer any guidance here? Is there somethign else I can do to clear
> those fake bad blocks (the underlying disks are fine, I scanned them)
> without rebuilding the array?

On Sun, Oct 30, 2016 at 06:02:42PM +0100, Andreas Klauer wrote:
> > There should be some --update=no-bbl --force if the admin knows the bad
> > block list is wrong and due to IO issues not related to the drive.
> 
> Good point. And hey, there it is.
> 
> mdadm.c
> 
> |                       	if (strcmp(c.update, "bbl") == 0)
> |                               	continue;
> |                       	if (strcmp(c.update, "no-bbl") == 0)
> |                                continue;
> |                       	if (strcmp(c.update, "force-no-bbl") == 0)
> |                               	continue;
> 
> force-no-bbl. It's in mdadm v3.4, not sure about older ones.

Oh, very nice, thank you. It's not in the man page, but it works:

myth:~# mdadm --assemble --update=force-no-bbl /dev/md5
mdadm: /dev/md5 has been started with 5 drives.
myth:~# 
myth:~# mdadm --examine-badblocks /dev/sd[defgh]1
No bad-blocks list configured on /dev/sdd1
No bad-blocks list configured on /dev/sde1
No bad-blocks list configured on /dev/sdf1
No bad-blocks list configured on /dev/sdg1
No bad-blocks list configured on /dev/sdh1

Now I'll make sure to turn off this feature on all my other arrays
in case it got turned on without my asking for it.

Thanks,
Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/  
```