Re: Expanding a RAID5 array

On 1 Jul, 05:45, Kari Uusimäki <uusim...@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
Carmine Castiglia wrote:
I am running an AlphaServer 1200 with a RAID Array 230/Plus subsystem
installed.  This question concerns a RAID 5 array consisting of three
DS-RZ1CB-VW (4.3GB) drives.

I would like to swap this out with DS-RZ1DB-VW (9.1GB) drives and would like
to do so in the easiest, safest, and quickest way possible.  I know that if
I replace a single 4.3GB drive with a 9.1GB drive and allow the array to
rebuild, the total storage space available will not change.  This rule
applies if I replace a second drive as well because available storage space
is always calculated based on the smallest drive in the array.  Correct?

So, what happens if I continue the process and replace the third drive.
After rebuild has completed, will the RAID controller automatically make the
full (18.2GB RAID 5) capacity available?  WIll this process be completed
without data loss?

Here you can find the specifications for the KZPAC (RAID Array
230/Plus).http://h18002.www1.hp.com/products/quickspecs/SOC/QB00E7PF.PDF

There you'll find the supported disks and the possible configurations.

I tend to recommend building a Raid 0+1 set (with as many disks as
possible) and when it is ready, to copying the data from old LUNs to
newly built LUNs using BACKUP/IMAGE. That way you'll get most disk space
with best performance and the downtime will take only as long as the
Raid 0+1 build and the BACKUP will take. The 9GB Ultra disks are the
fastest, but using more 4.3GB disks will give you a somewhat faster set,
because there are more spindles.

Using BACKUP for copying the data will also defragment your data as an
additional benefit.

Regards,

Kari- Hide quoted text -

- Show quoted text -

FWIW, we have a number of clients on SWXCRs inside DS10s using three
18GB disks and they work about as well as any SWXCR config would.
Personally, I dislike the SWXCR. It was great in its day but its day
is now all but over. If it were a new config and I could afford it,
I'd either host based shadow or use a SmartArray.

Steve
.

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