Re: Guest Partition Storage Configuration

[Jim Oberholtzer <midrangel@xxxxxxxxxx>]

First:  SSDs have their own characteristics that have to be taken into 
account.  I doubt based on the cost of them they would be used to 
provide virtual storage for a guest partition.  That would be a waste of 
technology in my view.

Your point about back up and recovery is valid, the IFS does have some 
weaknesses, and back up and recovery speed is one of them.

As to adding space to the partition, create new storage spaces as 
needed, link them to the guest OS.  They will show up there and you add 
them to the proper ASP the same as you would any other disk unit.  If 
you are using non-standard sizes (50Gb) then add  or two or more 50Gb 
storage spaces and be done with it.  I would keep the sizes of the 
storage spaces consistent.

Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


On 6/24/2011 9:13 AM, Jack Kingsley wrote:
> ok, how does this convey to the newer SSD??
>
> I see maybe 2 issues with this, you end up having more items to save per-se
> with more storage space objects and a longer restore window since the build
> time on storage spaces is quite significant from what I have seen on a
> restore of them.  What about sizing, if in the end you need additional
> storage for the storage space that you have defined, could it come back to
> cause you issues.  Example:  I need to add another 150GB of space to the
> current 3 spaces defined.
>
> On Fri, Jun 24, 2011 at 10:02 AM, Jim Oberholtzer<midrangel@xxxxxxxxxx>wrote:
>
> > >  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