Failed HDD question regarding suppression before replacing
 

Hi,
I just had an interview at a company with a heavy Linux environment and I was asked this question and wasn't quite sure:

If you have a hard drive in a raid array and it's throwing errors and needs replacing, but you see the drive is still in use: what command do you type to suppress the drive and show it as offline before physically removing the drive?

Thanks in advance!

So what was your answer?

"umount /dev/sd"[drive letter] ?

Not if it's in a raid array, the individual partitions are not mounted separately.

The answer is it depends on if it's a hardware vs software raid, and if hardware, what the manufacturer's tools are.

Damn! I blew that one then...so if it's a software raid what would need to be done?

I don't know off the top of my head, I'd have to look at the man page for mdadm (the Linux software raid manager).

If they use mdadm, then you do it like this. Replace the device names as required.

Fail the device if not already in a failed state
remove it
optionally zero out the superblock