adding hard drives to exising raid1
 

Hi! I'm a newbee to Linux. I'm using Redhat Linux Enterprise v.3. I have existing raid1 146 hard drives on a dell 2650 with Perc 3/di . I would like to add 2 more mirrored 146 drives. I have physically installed the drives but the system does not recognize the drives. I've looked in dmesg and messages. Help!!!

If you are using hardware raid it is not likely you can just add the disks and extend the array under any os. You would need to enter the SCSI bios to add the disks. Also many bios do not allow you to arbitrarily add disk to an array. You can often add spares but you would have to break the array to "extend" a file system.

If you want the ability to arbitrarily grow a given file system you may want to look into LVM (Logical Volume Management). With LVM you can grow and shrink a given fs "hot".

-Matt

Thanks for the info. If I wanted to add two more disk drives couldn't I go into the bios and initialize the drives and then create a separate container/array? Wouldn't It add them as sdb? When I do go into the bios I only see the two existing drives and not the two I just added. So the system does not see them at all.

Thanks for help,
Colleen

I was confused I though you wanted to extend an existing array or partition.
Yes that is true you can create a new array, which would show up as another scsi block device. If your SCSI bios is not detecting the new drives however you have another issue, which is not related to Linux. Are the drives seated firmly in the tray? Do you see the activity light blink on the new drives as the system boots? Pull one of the working drives out and compare the seating of the working drive to one that is not working?

-Matt

Hi Matt -

Thanks for all your help. I did re-seat the hard drives and that didn't work. I have two other hard drives that did work. I'm returning the bad drive(s) to the vendor. I would like to thank you again and everyone else in this forum, being new to Linux Administration I find it very helpful.

- Colleen