Re: Virtual disks for an i partition

[Pete Helgren <pete@xxxxxxxxxx>]

Thanks Sue.  Nice to have a  BCS'er watching the list.  IIRC my JS12 has 
two 146GB drives which I guess I mirrored (I remember being confused 
about it at the time - that AIX verbiage took a little getting used 
to).  So the 6 drives I have in the storage module (146GB each) are the 
ones I am going to look at reconfiguring.  I'll have to refresh my 
memory on the config options on the storage modules.  Once I get a full 
volume configured, I'll probably go for carving out 6 - 35GB drives for 
each partition (6.1 and 7.1)

Thanks for the info.  Now to back it all up and "start over"...

Pete Helgren
www.petesworkshop.com
GIAC Secure Software Programmer-Java

On 2/12/2013 6:34 PM, Sue Baker wrote:
> Pete, a bladecenter-s (BCS) is a little bit of a different critter than
> the servers Pete, Larry, and Rob work on.  That said, here are some
> answers to your questions.
>
>
> On 2/11/2013 3:54 PM, Pete Helgren wrote:
> > I seem to recall that the recommendation for VIOS installation use two
> > mirrored physical disks but now I am not so sure that is necessary if
> > the 6  320 GB drives in the SAS cage were one volume and then two
> > smaller virtual disk were carved out for VIOS.  Is my assumption about
> > physical disks for VIOS incorrect?
> Yes, VIOS should protect the disk used for rootvg.  However, if my
> memory serves me, you will use the disk on the blade for rootvg, not the
> disks in the BCS, so protecting it becomes problematic because there's
> only 1.  (My memory may be failing me on that point!  There may be 2
> disks on the blade, in which case, you would run mirrorios to get disk
> level mirroring.)
>
> > If I understand Rob and the good Doctor correctly, I should carve out at
> > least 6 virtual disks for IBM i?  Then in IBM i I also create a RAID
> > array from those 6 disks (or is that redundant?)
> IBM i cannot "turn on RAID" protection for the drives in a BCS.  You
> will either create parity sets from VIOS or you'll give the drives
> straight to IBM i and use mirroring to protect them.
>
> Regardless, if you need good save/restore performance, you certainly
> want to have at least 6 "disks".  If save/restore isn't critical, you
> can get by with 2-5 "disks".  My testing showed that getting to 6 drives
> cut average save/restore times in half when compared to any
> configuration of fewer disks.
>
> > I guess I never fully virtualized my thinking:  The configuration of IBM
> > i on VIOS should mimic a physical configuration. Yes?
> With the BCS hardware, you can have it mimic a physical configuration,
> but it doesn't have to.