Re: mke2fs hung

> I switched to a second console to look at the issue and found that 
> stderr tmpfile for mke2fs contains "Found a dos partition table in 
> /dev/sda2" and stdio tmpfile "prompts" with "Proceed anyway? (n/Y)". 
> Giving a 'y' in the main console lets it proceed, but it shouldn't 
> have stopped.
>
> It seems the wipefs -af /dev/sda* before parted is not enough. Maybe a 
> second wipefs is needed between parted and mkfs [*]?
>
> IIUC it's quite a corner case (new gpt partition overlapping an old 
> dos extended partition), but probably it's better to handle it.
>
In the past I stumbled across that issue as well. So I created a hook 
'mountdisks.DANGEROUS' that includes, among others, the following lines:

<snip>
# Clear any MD arrays:
if [ $(grep md0 /proc/mdstat) ]; then
     mdadm --stop /dev/md0
fi
if [ $(grep md1 /proc/mdstat) ]; then
     mdadm --stop /dev/md1
fi

if [ $(grep md /proc/mdstat) ]; then
     # Clear the whole disks:
     mdadm --zero-superblock --force $DISK_A

     # Clear arrays using a partition (e.g. a swap partition):
     mdadm --zero-superblock --force ${DISK_A_SWAP}
fi


# Clear the partition table:
sgdisk --zap-all $DISK_A
<snip>

Somehow redundant, I know, but I had issues with mdadm before. Never had 
a problem ever since. But be careful - this ensures that the disk gets 
completely wiped and no partition is preserved, even if you have a 
'preserve' statement in your disk_config.