Re: Guest Partition Storage Configuration

[Jim Oberholtzer <midrangel@xxxxxxxxxx>]

Mark,

It does not matter if the disk units are virtualized by VIOS or IBM i.  
The point is; IBM i manages disk in a specific way, and if you let it, 
it will be very efficient.  IBM i does have its limits and one of them 
is it likes lots of disk arms to manage.

The fact that VIOS and IBM i can both virtualize the environment does 
not alter the concept that the guest IBM i does not know it's running in 
virtual environment.  That's the whole point behind virtualization, mask 
the hardware implementation from the guest partition.    Let IBM i be 
good at what it's good at, one of which is managing disk storage better 
than any other OS.  That comes a price, that being you have to provide 
it sufficient disk arms to manage.

(sorry if this is starting to sound a bit harsh, it's not meant to....)

Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


On 6/24/2011 9:11 AM, Mark S. Waterbury wrote:
> Hi, Jim:
>
> But why is this even necessary, when the virtual disk space is carved
> out from single level storage on the host system, if hosted on i5/OS,
> and (presumably) is itself spread across all available drives, heads and
> arms?
>
> Or, are you talking specifically about the case where the virtual disk
> is provided by VIOS, and hosted on a SAN of some kind?
>
> Thanks for any further clarifications you can provide.
>
> Mark S. Waterbury
>
>   >  On 6/24/2011 8:11 AM, Jim Oberholtzer wrote:
> > >  The reason is to provide IBM i with arms to manage.  Creating one
> > >  storage space would be the same as giving an IBM i instance only one
> > >  disk drive.  Bad plan from an I/O performance stand point.  The
> > >  architecture just works better when it's allowed to do what it is
> > >  designed to do.
> > >
> > >  Jim Oberholtzer
> > >  Chief Technical Architect
> > >  Agile Technology Architects
> > >
> > >
> > >  On 6/23/2011 3:19 PM, Jack Kingsley wrote:
> > > >>  Jim, curious, I never heard of having a storage space only based on 35GB??,
> > > >>  could you elaborate on this part.  If I need 150GB of space I would just
> > > >>  create 1 storage space.
> > > >>
> > > >>  On Thu, Jun 23, 2011 at 4:01 PM, Evan Harris<auctionitis@xxxxxxxxx>    wrote:
> > > >>
> > > > > >>>>     Yes, the partition will be created with a HMC
> > > > > >>>>
> > > > > >>>>     On Fri, Jun 24, 2011 at 12:04 AM, Jack Kingsley
> > > > > >>>>     <iseriesflorida@xxxxxxxxx>    wrote:
> > > > > > >>>>>     >    Evan, are you creating this with an HMC or ??
> > > > > > >>>>>     >
> > > > > > >>>>>     >    On Wed, Jun 22, 2011 at 6:21 PM, Evan Harris<auctionitis@xxxxxxxxx>
> > > > > >>>>     wrote:
> > > > > > >>>>>     >
> > > > > > > >>>>>>     >>    Hi Jim
> > > > > > > >>>>>>     >>
> > > > > > > >>>>>>     >>    Thanks again for all the feedback. Your guess about the memory may
> > > > > > > >>>>>>     >>    well be correct - I know the machine in question did not have loads of
> > > > > > > >>>>>>     >>    memory at the time.
> > > > > > > >>>>>>     >>
> > > > > > > >>>>>>     >>    --
> > > > > > > >>>>>>     >>    Regards
> > > > > > > >>>>>>     >>    Evan Harris
> > > > > > > >>>>>>     >>    http://www.auctionitis.co.nz
> > > > > > > >>>>>>     >>    --