Configuring RAID 1 on a Enhance Technology R4SA EnhanceBOX eSATA

My place of employment has this under-utilized Enhance Technology R4SA EnhanceBOX 1U 4-Bay 4-port eSATA Disk Array Enclosure, with each bay having a 1.5 TB drive. You can see the back of it here by scrolling down. If I’m understanding the configuration in order to get a RAID 1, I’d need a 4 port e-sata controller. However we have a 2-port e-sata card and so far I’ve tested one of the drives and I know it at least works. If I were to use just 2 drives how can I get them in a RAID 1 mirror? We are on Fedora so is mdadm the way to go? I see a tutorial here and here. I also take it I’d have to start from scratch?

I looked at that and read the description. Their terminology is a bit confusing because it seems they describe an enclosure that has 4 connected drives, yet it has 4 eSATA ports on the back.

Have you tried connecting your system to all the ports, one at a time, and is each drive totally independent of the others? If so, then I guess that yes, you would need 4 eSATA ports on your system to connect to the 4 drives.

That being the case, then yes, mdadm would be the easiest way to set up a 2 drive array in raid1. You could mirror the physical device easily.
To carry the idea a little further, if you are using LVM then the 2 physical devices could become 2 logical volumes and the logical volumes could be set up as raid1. If later you activate the other 2 drives they could be added to the same VG and used to expand the LVs. That likely would not require any changes to the raid configuration.

The official documentation on how to use raid on fedora is here

I did and yes all mount with a different device ID.

What’s the GUI shown here? Blivet? Gparted?

Ok thanks for the tip to use a LVM.

That would require a new esata card. Not sure if any metadata would be cached from the 2 port to a new 4 port? And would the RAID LVM still be in tact? I did this recently with a Dell PERC and I had to recreate the disk array but all data was there.