Thread (6 messages) 6 messages, 3 authors, 2021-06-17

Recovering RAID-1

From: H <hidden>
Date: 2021-06-13 22:56:36

I am running CentOS 7 and would like to see if I can "recover" a lost(?) RAID-1 setup on two identical SSDs and would greatly appreciate some assistance.

Part of the history is that I many months ago used Intel fake RAID on the motherboard but I /think/ I may also have used software RAID... The motherboard was replaced and because there were some issues I eventually abandoned the fake RAID and did not have mdadm running at that time. Thus, I have been operating off the two identical disks in non-RAID mode but would now like to see if I can get back to having RAID-1 running using mdadm only. There have been a number of OS updates, new software installed and work done on the computer since but it is running fine.

Because I have no notes and really did not know what I had done before the above motherboard replacement I have to tread very carefully. Here is my current understanding:

- mdadm is installed on the system

- the two relevant disks are currently /dev/sdb and /dev/sdc (I also have two other disks in the system that are, for this purpose, irrelevant)

- gparted tells me that both disks are 238.47 GiB in size with:

-- /boot/efi of 260 MiB

-- /boot 1.00 GiB and formatted xfs

-- (LUKS) encrypted partition 247.22 GiB

-- unallocated 4.34 MiB

- gparted further shows a key symbol next to /dev/sdc1 and /dev/sdc2 and /dev/sdb3 but not /dev/sdb1, /dev/sdb2 and /dev/sdc3. Googling this it suggests that partitions with keys are in use and the ones with /no/ keys are /not/ in use?

- am I correct therefore that the system booted from /dev/sdc1 and /dev/sdc2 and using /dev/sdb3 for everything /but/ /boot and /boot/efi?

- cat /proc/mdstat does not show any RAID information

- my /uneducated/ guess is that there /might/ be some RAID-information in the last 4.34 MiB but I am not sure how to check it?

- my next /uneducated/ guess is that, if so, mdadm 0.90 was/could be used since that is the version that seems to use space at the end of the disk

I would very much appreciate if anyone can suggest how to check the last items? Once this has been verified the next step would be to get mdadm RAID-1 going again.

If any of the above is incorrect in whole or partially, please advise.

Thanks!
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