CentOS - Mar 2023 - Mount removed raid disk back on same machine as original raid

I have a Centos 7 system with an mdraid array (raid 1).? I removed a 
drive from it a couple of months ago and replaced it with a new drive.? 
Now I want to recover some information from that old drive.

I know how to mount the drive, and have done so on another system to 
confirm that the information I want is there.

My question is this:

What is going to happen when I try to mount a drive that the system 
thinks is part of an existing array?

To put it another way:? I had two drives in md127.? I removed one (call 
it drive1), and replaced it with a new drive.? Some files were 
accidentally deleted from md127, so now I want to connect drive1 back to 
the same machine and mount it as a separate array from md127 so I can 
copy the files from drive1 back to md127.? What do I need to do to make 
that happen?

Thanks,

Bowie

Once upon a time, Bowie Bailey <Bowie_Bailey at BUC.com>
said:
> What is going to happen when I try to mount a drive that the system
> thinks is part of an existing array?
I don't _think_ anything special will happen - md RAID doesn't go
actively looking for drives like that AFAIK.  And RAID 1 means you
should be able to ignore RAID and just access the contents directly.

However, the contents could still be a problem.  If LVM was in use on
it, that will be a problem, because LVM does auto-probe and will react
when it sees the same UUID (IIRC LVM will only block access to the newly
seen drive).  I don't think any filesystems care (I know I've mounted
snapshots of ext4 and IIRC xfs on the same system, haven't touched
btrfs).

-- 
Chris Adams <linux at cmadams.net>