[Beowulf] Mix different drives in RAID (WD4000YR and WD5000YS)

Karen Shaeffer shaeffer at neuralscape.com
Wed May 21 12:58:18 PDT 2008

On Wed, May 21, 2008 at 11:22:27AM -0400, Yaroslav Halchenko wrote:
> Hi Beowulfers,
> I had 1 drive failed in the RAID (WD4000YR) so I sent it for replacement
> and got back (WD5000YS), so it is of similar series but larger in
> capacity. Performance metrics of replacement seems to be at least as
> good as of old one. But I still wonder if RAID would digest it nicely
> (we use Areca ARC1160) and I don't want to try it hard way (ie use
> new one as a spare and wait until raid fails and starts rebuilding).
> Areca controller has Capacity Truncation capability so larger size of a
> new drive should be (theoretically) ok, but I still wonder what
> implications I might encounter. May be someone could share ideas or
> experience?
> Thanks in advance!

They are both SATA-2 (3Gb/s) HDDs. With the replacement drive
at 500GB, it should work well for you. The raid controller
will ignore that last 100GB. You need to check the firmware
version on the replacement drive. Sometimes there are firmware
updates that aren't well publicized. That is a common problem.
This class of drives can usually be configured to run at
either 1.5Gb/s or 3.0Gb/s, with a jumper on the drive. You need
to check that. There are other optimizations available in the
newer SATA2 implementations you might want to consider.
http://en.wikipedia.org/wiki/Serial_ATA is a good place to
start learning. Good luck with it.

My advice comes without warranty of any kind. YMMV.

 Karen Shaeffer
 Neuralscape, Palo Alto, Ca. 94306
 shaeffer at neuralscape.com  http://www.neuralscape.com

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