When configuring RAID it’s quite important to have the same partition tables on every disk. I’v done this many times on msdos partition tables like this:

sfdisk -d /dev/sda | sfdisk /dev/sdb

but it’s not working any more on GPT partition tables. Hopefully it still can be done but with different toolstack 😄

Install gdisk:

apt-get install -y gdisk

Then use sgdisk like this:

sgdisk -R /dev/sd_dest /dev/sd_src
sgdisk -G /dev/sd_dest

First command will copy partition from /dev/sd_src to /dev/sd_dest. Second will randomize partition UUID’s - needed only if you want to use disks in same machine (this is my case).