[CentOS] Kernel panic after removing SW RAID1 partitions, setting up ZFS.

[Benjamin Smith]

On Tuesday, April 9, 2019 2:53:55 AM PDT Simon Matter via CentOS wrote:
> > I think it's because you clobbered md0 when you did --zero-superblock on
> > sd[ab]1
> > instead of 2.

As mentioned in another reply, this was a typo in the email, not on the 
machine. 

I drove to the site, picked up the machine, and last night found that the 
problem wasn't anything to do with mdadm, but rather setting a partition to 
GPT. For some reason, you *cannot* have a partition of type GPT and expect 
Linux to boot. (WT F/H?!?) 

So I changed the type of the partitions used for the ZFS pool to Solaris (just 
a random guess) and it's all working beautifully now. Don't know if that's 
recommended procedure as I've always used whole disks for ZFS pools, and a 
little Google pounding gave no useful leads. Many examples of using partitions 
or files as HW devices in a ZFS pool, but no info on what partition *type* 
should be used. 

Next up: escalating this with the CentOS list...