Iain,

On Wed, 20 Jun 2001, Iain Campbell wrote:
> man raidtab says
> 
>   failed-disk index
>     The  most recently defined device is inserted at position index in
>     the raid array as a failed device. This allows you to create  raid
>     1/4/5  devices  in  degraded mode - useful for installation. Don't
>     use the smallest device in an array for this, put this  after  the
>     raid-disk definitions!
>
> I can see that it would be possible to build a RAID in degraded mode,
> but how will this help installation, and installation of what, anyway?

I think that the reason installation is mentioned is if you want to
install onto a RAID array, but not all the disks are available (perhaps
they have previously failed, or they are holding the original data).

For instance, say you have a server with a 40G disk, and you want to
upgrade it to a RAID-1 mirror of two 40G disks... you could install on the
new (unused) 40G disks as a degraded RAID-1 mirror of the new disk and
/dev/null (as a failed-disk). Then, once up and running you could copy
everything from the old-disk to the degraded raid array, and once the old
disk is no longer needed to store the data, add it to the RAID array and
resync it.

Regards,

Corin

/------------------------+-------------------------------------\
| Corin Hartland-Swann   |    Tel: +44 (0) 20 7491 2000        |
| Commerce Internet Ltd  |    Fax: +44 (0) 20 7491 2010        |
| 22 Cavendish Buildings | Mobile: +44 (0) 79 5854 0027        | 
| Gilbert Street         |                                     |
| Mayfair                |    Web: http://www.commerce.uk.net/ |
| London W1K 5HJ         | E-Mail: [EMAIL PROTECTED]        |
\------------------------+-------------------------------------/

-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to [EMAIL PROTECTED]

Reply via email to