Re: Where do I find the definitive man page for mdadm?

[Dan Ritter <dsr@randomstring.org>]

Gene Heskett wrote: 
> On Friday 12 November 2021 08:49:21 Dan Ritter wrote:
> 
> Ok, zeroed them, nuked mdadm.conf & rebooted.
> gparted each one, setting 2 partitions in GPT format on each of 900000 
> MIB (sde1) with label MDV1 and 5000 MIB (sde2) labeled MDV2 and applied 
> that to each of the 4 drives. Double check as /dev/sdf somehow swapped 
> positions on the drive, fixed that: Wash rinse and repeat for sdf, sdg, 
> and sdh with labels of MDX1, MDX2, MDY1, MDY2 and MDZ1 and MDZ2. And of 
> course gparted makes a file system when Apply is clicked.
> 
> but:
> root@coyote:~$ 
> mdadm -C /dev/md0 --level=10 --raid-devices=4 /dev/sde1 /dev/sdf1 /dev/sdg1 /dev/sdh1
> mdadm: /dev/sde1 appears to contain an ext2fs file system
>        size=921600000K  mtime=Wed Dec 31 19:00:00 1969
> mdadm: /dev/sdf1 appears to contain an ext2fs file system
>        size=921600000K  mtime=Wed Dec 31 19:00:00 1969
> mdadm: /dev/sdg1 appears to contain an ext2fs file system
>        size=921600000K  mtime=Wed Dec 31 19:00:00 1969
> mdadm: /dev/sdh1 appears to contain an ext2fs file system
>        size=921600000K  mtime=Wed Dec 31 19:00:00 1969
> Continue creating array? yes

You should stop there and run wipefs. I note from later mail in
this thread that you didn't; and then you had to reboot.

With the array not started, or stopped, run wipefs on each of
the partitions.

Then these -C commands should work well without warnings, and
creating a filesystem on the /dev/mdX devices will proceed
without warnings or errors.

> There are a few unallocated blocks at the ends of all drives. gparted 
> chose alignment and prespace in MiB. Do I need to add a 3rd partition to 
> use them up? All drives seem to be identical sizewise but the pages 
> recommend identical partition sizes. Theoreticly I could expand the 
> smaller partition to use it up.

I would not bother.

-dsr-