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

- From: Marc MERLIN \<hidden\>
- Date: 2016-11-04 18:50:40 
- List: linux-raid
- Page: https://ratatoskr.run/linux-raid/2016/11/6633331
- Thread: https://ratatoskr.run/linux-raid/2016/10/6633249/t.md

```text
On Fri, Nov 04, 2016 at 02:22:48PM -0400, Phil Turmel wrote:
> On 11/04/2016 02:18 PM, Marc MERLIN wrote:
> 
> > Right, so I thought I was home free, but not even close. My array is
> > back up, the badblock feature is disabled, array reports clean, but I
> > cannot access data past 8.8TB, it just fails.
> > 
> > myth:~# dd if=/dev/md5 of=/dev/null bs=1GB skip=8797
> > dd: reading `/dev/md5': Invalid argument
> > 0+0 records in
> > 0+0 records out
> > 0 bytes (0 B) copied, 0.000403171 s, 0.0 kB/s
> > myth:~# dd if=/dev/md5 of=/dev/null bs=1GB skip=8796
> > dd: reading `/dev/md5': Invalid argument
> > 1+0 records in
> > 1+0 records out
> > 1000000000 bytes (1.0 GB) copied, 10.5817 s, 94.5 MB/s
> 
> That has nothing to do with MD.  You are using a power of ten suffix in
> your block size, so you are running into non-aligned sector locations.

not really, I read the whole device from scratch (without skip) and it
read 8.8TB before it failed. It just takes 2 days to run, so it's a bit
annoying to do repeatedly :)

myth:/dev# dd if=/dev/md5 of=/dev/null bs=1GB skip=8790
dd: reading `/dev/md5': Invalid argument
7+0 records in
7+0 records out
7000000000 bytes (7.0 GB) copied, 76.7736 s, 91.2 MB/s

It doesn't matter where I start, it fails exactly in the same place, and
I can't skip over it, anything after that mark is unreadable.

I can switch to GiB if you'd like, same thing:
myth:/dev# dd if=/dev/md5 of=/dev/null bs=1GiB skip=8190
dd: reading `/dev/md5': Invalid argument
2+0 records in
2+0 records out
2147483648 bytes (2.1 GB) copied, 21.9751 s, 97.7 MB/s
myth:/dev# dd if=/dev/md5 of=/dev/null bs=1GiB skip=8200
dd: reading `/dev/md5': Invalid argument
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.000281885 s, 0.0 kB/s
myth:/dev# dd if=/dev/md5 of=/dev/null bs=1GiB skip=8500
dd: reading `/dev/md5': Invalid argument
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.000395691 s, 0.0 kB/s

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/                         | PGP 1024R/763BE901
```