Answer by Jason Byrne for Why does the partition start on sector 2048 instead of 63?

While I realize that the actual question was answered, a quick fix for the 63 vs 2048 first cylinder issue is something like:

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

(if you're sure you've got drives that are the same size)

You can then proceed with adding the various partitions back into the RAIDs where you got complaints about the partitions not being the same size due to the 63/2048 start cylinder difference throwing off the eventual partition sizes.