Hi,
On Mon, 2 Nov 1998 22:03:34 +0100 (CET), MOLNAR Ingo
<[EMAIL PROTECTED]> said:
> On Mon, 2 Nov 1998, Jorj Bauer wrote:
>> Are there any plans for the ability to add and remove mirrors on the fly?
> echo "scsi remove-single-device 0 0 3 0" >/proc/scsi/scsi
> (the numbers identify the SCSI disk). I will add explicit support (with
> apropriate safeguards) for working-disk removal. It's really simple, it's
> just not there yet because there was no reason.
Ingo, there's one thing you could add which would be less simple, but
would be impressive as anything: dynamic raid1-style mirroring on the
disk to be replaced. Tell the kernel to start removing an existing
disk, and it can choose a hot spare to act as a replacement for that
disk. You then have a window in which you can treat the old disk and
the new one as a broken raid1 set needing synchronised. Once the hot
spare is up to date you can atomically update the entire raid set so
that the hot spare becomes active and the disk we wanted to remove is
now itself a hot spare.
That way, we can remove any disk from the array with no loss of
redundancy at any point in time.
--Stephen
