Re: Am I RAIDed or mirrored

You could do that to check to make sure the drive is good. BUT... just adding the drive in will not alter the raid striping. What you really want is the raid set built on all four drives. The only way I know to do that is to reload. If you go to reload and the fourth drive won't light up even then, well, that's what the warranty is for... 1-800-ibm-serv gets a call for bad hardware.

IBM did what the order told them to do... 4 drives raid with hot standby. That's 3 in raid and 1 standby.

AFAIAC hot standby really demands at least 5 drives. I always recommend 4 drives as an absolute minimum.


Aaron Bartell wrote:

So maybe I should try just adding the fourth drive to the array and see if
that works first? Is there a way to check and see if the parity is setup
correctly after I add that drive to the array?

Should IBM have done this by default?

And yes, Bruce, we just got done with our first round of trick-or-treating.

Aaron Bartell
http://mowyourlawn.com


On Sat, Oct 31, 2009 at 11:17 AM, Lukas Beeler <
lukas.beeler@xxxxxxxxxxxxxxxx> wrote:

On Sat, Oct 31, 2009 at 15:48, Trevor Perry <trevor@xxxxxxxxxx> wrote:

Why would you not just add the disk to the RAID set and let it balance?

It

is, after all, a fresh server with not a lot of DASD used yet.

I suggested that possibility - point is, that 3-Disk RAID sets are a
special case, they performed very badly on Power 5 520's. Now, the
controller hardware and all has changed a lot, and just adding the
disk might very well work just as it should. I know this was a bad
idea on the older systems.

But especially because there's not much data on it yet, doing the
whole rebuild array shtick should be fairly easy to do.