Re: Guest Partition Storage Configuration

[Jim Oberholtzer <midrangel@xxxxxxxxxx>]

Each storage space is presented to the guest partition OS (regardless of 
the OS) as a single DASD unit.  So in the case you suggest there would 
be three disk 50Gb units showing up in the OS.  For Linux or WinDohs, 
that's sufficient because they do not use single level storage.  For IBM 
i, it would not provide an I/O footprint that would allow IBM i to 
optimize its I/O.  Better to provide 5 units at 35Gb (175 total) than 
three 50Gb units.  Another small factor in setting up guest IBM i 
partitions, try to mimic the same size drives as are supported by the 
OS.  I pick 35GB because there are more total arms, and it is a well 
known size.  70Gb are fine as well, however you would only wind up with 
two or three units, and that could spell trouble for the I/O performance.

Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


On 6/24/2011 8:08 AM, Jack Kingsley wrote:
> Just to clarify this then, 1 storage space of 150GB would have 1 disk arm, 3
> of 50GB each would then possibly use 3??  I really didn't think about this
> aspect of creating storage spaces is why I ask.
>
> On Fri, Jun 24, 2011 at 8:11 AM, Jim Oberholtzer<midrangel@xxxxxxxxxx>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