Why Are My sda and sdb Drives Almost Identical?

You've got quite a unique setup with those mirrored drives. It looks like you have two EFI system partitions, with one actively in use and the other presumably in sync. Your boot partitions and the rest are nicely arranged into an MDRAID mirror and LVM groups. If you didn’t set this up, it's best to keep your paws off without clear documentation! Also, I noticed that /dev/sdc is being used without a partition table – that's a bit unusual but it might be intentional for your specific setup.

As you guessed, since you're using md for RAID1, it's normal for the sda and sdb to look very similar, especially their partitions. Just keep in mind that your sdc drive, where you're storing data, isn't covered by RAID protection, so it's a bit vulnerable – if it fails, your data could be lost. It's wise to ensure that critical data is backed up elsewhere. Don't forget to check out the details with commands like /proc/mdstat and mdadm!

It seems like you have them set up in a RAID1 configuration, which is designed to create two mirrored copies of the same data. So, yes, seeing them appear identical is totally expected! That's how RAID1 works – it provides redundancy by duplicating everything between the two drives.