RAID Failure and Recovery Ubuntu Linux mdadm

My Ubuntu 21.04 Network Attached Storage Server (NAS) had a failed mdadm RAID 5 Array because 1 disk failed with bad blocks.

I recovered the RAID Array by purchasing a new Seagate IronWolf 4tb Drive and adding it back to the Raid 5 Array. The rebuild took about 8 hours.

Techworks

[jptrainor]

I have a RAID 6 array (four drives) that's been running in an Ubuntu 10.04 server since 2010. Now, 12 years later, one of the drives doesn't pass a SMART health check. It hasn't failed yet, but it's coming. The RAID array has never had a problem in 12 years. And I have a spare drive in already, because I bought one extra to have on hand when this day came. I wasn't expecting it to be 12 years later.

[nickswebtsv]

Great video, watched in it full. I'm in the middle of learning about mdadm.

[BramHarmsen]

Thanks for the video, very helpful to see the whole process. Im investigating if a raid 5/6 setup would be usefull for me as well. The thing that I worry about the most is not being able to rebuild the array after a drive failure due to a URE. Im planning on using 6 or 8TB drives. Can you elaborate of the rist and what would actually happen in such scenario? Especially how much data will be lost. Is here a chance to loose the whole array for example?

[pastyboi]

do you mind sharing your raid health check script?