My system right now is running fine. I am asking this question just in case it does happen. I have redhat 8.0 running and a software raid 1 with 2 hard drives. My question is if one of those drives were to fail what would be the proceedur for replacing the bad drive? I just realized that I have no clue what to do if this happens.

Thanks for your help

It depends on your controller. You will often find that there is a option to mirror the drives in a setup section just after the point you would usually enter the BIOS. Personnaly I would rather do it this way as the server would be offline and not handling live data during the update. Other controllers will automatically mirror the data others you may need to run a software command - I would refer to the RAID controller manufacturers instructions.

With linux I have only ever done it witht the server offline.

That would be great if I had a controller. I have this setup on a software raid. I just set this machine up for a basic server and didn't want to spend the money for controller. As a matter of fact I didn't spend any money on this computer, it was one of the old ones we had. I put a second hard drive in installed redhat with a software raid.

I'm afraid I have never done this. From what I can see in the documentation you need to edit "/etc/raidtab" then run "mkraid" or "mkraid -f" if there is data on the drive.

First of all, the quality of the md kernel driver (the component that provides RAID fucntionality) is exceptional, and the data rates that i was getting when testing this setup rivalled those of HW controllers quite favourably...

Ok, now that this is out of the way, *IF* one of your disks fails, you will not have to do anything. md will flag the disk as failed (you'll be able to see this by doing cat /proc/mdstat) and when you replace the disk, md will pick this up and rebuild it as a mirror (you'll also be able to see the resyncing process by doing cat /proc/mdstat).

As a sidenote, if you really want to get into admin of RAID servers, you should get the new, updated tools for using RAID via md. They are called mdadm and they have a plethora of options to do just about anything with RAIDs.

The url :

http://www.cse.unsw.edu.au/~neilb/source/mdadm/

Here you can get the tarballs, and (maybe) rpms too. The old (i.e. 'mkraid') tools are not supported anymore and if you want to use RAID you should use mdadm.

I hope this helps,

Cheers,

Vlad.

Great that is a great help. Thanks guys, if you think of any thing else I should know please post it. I like to take in as much info as I can.

Thanks again