Re: Adding a disk to a RAID array

On Fri, 2003-03-14 at 12:08, Elizabeth R Martin wrote:
> You are correct in that the OS sees only 1 drive /dev/sda because the hardware
> raid controller card takes care of all the RAID stuff.  I am rung RAID 5
> currently with 3 drives, I want to add a 4th, it has been sitting in a cabinet
> for when needed.  The drive is then partitioned according to the information I
> posted sda1, sda2, etc.  Once I get the new hard drive installed in the BIOS of
> the controller card, it will create the /dev/sda seen by the OS as a larger
> drive with the end of the drive not being used.  I know that I have to some how
> edit fdisk manually so that sda4, the extended partition, ending # shows the new
> end of the partition.  I then have to manually edit fdisk again so that the
> ending # on sda6 shows the end of the partition and then restore the data.  Like
> I said I remember manually doing this once before a long time ago but the Unix
> Guru who helped me then is no longer here.  This is something that I will have
> to plan downtime for since this is a critical system and I don't want to make to
> many mistakes with the changes.

Liz,
Before doing this, make sure your RAID controller can add a new disk to
an existing RAID 5 array. I think most RAID controllers can not do this,
mostly due to the nature of RAID 5. If there is any doubt about this, I
would suggest making a full backup of the filesystems on the array,
install the drive, create a new RAID 5 array with the 4 disks, and
restore.

If you are completly sure your RAID controller can add a new disk to an
existing array, then the tool you want is probably parted, which will
both extend your partition table, and the filesystem within it.

Cheers,
-- 
Javier Gostling                        Av. Kennedy 5757, of. 1502
Ingeniero de Sistemas                  Las Condes, Santiago, Chile
Virtualia S.A.                         Fono: +56 (2) 202-6264 x 130
[email protected]                 Fax:  +56 (2) 342-8763