RE: Mixing Disk Drives?

And that the new RAID-6 controller doesn't have near the cache of the
still-only-at-RAID-5 2780.  Bleh!

--
Justin C. Haase - iSeries System Engineer
IBM Certified Systems Expert - eServer i5
Kingland Systems Corporation

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Larry Bolhuis
Sent: Monday, March 20, 2006 11:31 AM
To: Midrange Systems Technical Discussion
Subject: Re: Mixing Disk Drives?

Re-Striping is never automatic. You must select the RAID set in question
(In this case the only one) and select STOP RAID. Then turn right around
and do START RAID and this set will be rebuilt with stripe data on all 8
drives (in this case 12.5% loss per drive)

I have done this isn some cases but because it requires your data be
unprotected from the beginning of Stop RAID to the end of Start RAID you
should have a good SAVE 21 or SAVSTG backup handy just in case.  You
will likely not gain any performance in this case except when there is a
failed drive. You gain NO additional protection with the striping on 2 4
or 8 drives. In any case if you lose one drive, you're OK, lose two
you're toast. 

Note that there is ONE new controller for V5R4 that supports RAID 6
which allows you to lose two drives and survive. Of course you lose two
drives worth of capacity in a RAID 6 set.

  - Larry

Chris Bipes wrote:
> This has to be done in restricted state.  I don't know if adding the 
> 8th's drive will re-stripe or not.  Perhaps someone else can chime in 
> here.
>
>
> Christopher Bipes
> Information Services Director
> CrossCheck, Inc.
>
> -----Original Message-----
> Sent: Monday, March 20, 2006 8:54 AM
> To: Midrange Systems Technical Discussion
> Subject: Re: Mixing Disk Drives?
>
> Chris, can you explain the steps involved with rebuilding the raid
set?
>
>