Re: [PATCH] for Multiple Device driver - md.c (kernel 2.4.12)

[Ingo Molnar]

On Thu, 11 Oct 2001 [e-mail] wrote:

> Suppose you can hot-swap a hard disk in a system. Now if you have a
> degraded Software RAID device (for example a RAID-5 with one disk
> failed) and you replace the failed disk on-the-fly you cannot start
> reconstruction (with raidhotadd) of the Software RAID device with the
> replaced disk because it says it is BUSY.

this is possible already: you should first raidhotremove the failed drive,
then raidhotadd the new drive. It can be the 'same' drive if it's a
hot-swap disk, or it can be another, spare disk.

> +	if (rdev && rdev->faulty) {
> +		err = hot_remove_disk(mddev, dev);

what your patch does is a forced remove of any drive that is
raidhotadd-ed. This is less finegrained than the current solution, and
might make the method more volatile. (easier to mess up accidentally.) Is
there anything your patch allows that is not possible today, via
raidhotremove+raidhotadd?

	Ingo