Re: Disk Size for Nest OS Release of IBM i

It's not a physical disk thing for the SCSI world because no SCSI machine will run IBM i 7.2 so scratch that.

*IF* (and this is DrFranken's guess) they stuck with the physical disk thing then 70GB is the smallest physical disk you can attach to a SAS based machine, which is to say Power6 and up. No you cannot purchase new 70GB SAS disks any longer BUT if i 7.2 is to support a Power6 machine which might legitimately have 70GB disks in it, there you go.

That said I seem to recall conversations at last year's annual COMMON conference that they picked 70G for a different reason.

We at iInTheCloud and iDevCloud do not like this 70G minimum for our small personal partitions especially as that's more disk space than any of our personal partitions even use today in total!

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 1/22/2014 4:36 PM, Kirk Goins wrote:

It has been mentioned here that V7R2 ( or whatever the new release will be
called ) will require a 70GB Loadsource.

The real question here is what size to we really need? I believe this 70GB
drive spec is based in the older SCSI drives not the physical space
required. Where I am going with is vSCSI disks presented to IBM i from VIOS
or a Hosting IBM i partition or even the size of disks that a SAN will
present to IBM i.

Let's talk 70GB SCSI Drives. If I Mirror my LS with a pair of 70GB drives
then the OS will see 70GB. If my 70GB LS is part of a 4 drive Raid set I
will see only about 53GB. INa 3 drive set I don't know as I Haven't done a
3 drive set but if everything is even that will make those drives around
47GB.


Here's why I ask.
New Power7 with 8 139.5 drives. After Raid5 those drives are 122GB In this
exampleI want to have an IBM i Hosting partition and 2 IBM i Guests. IBM
suggest to have a minimum of 6 vSCSI drives in a partition for
performance. Now in creating cSCSI drives in IBM i for an IBM i Guest you
loose about 7% if I remember correctly. So each drive on the host needs to
be about 75GB to present 70GB to the guest. So I need 12 of these. ( 12 x
75 ) = 900GB that will leave about 76GB in the HOST. or about 71% usable if
you keep the HOST at 90% used. If I can use slightly smaller drives I would
a little more breathing room or room for a set of OS Image catalogs etc.

No in this example I don't want run any work other than hosting in the HOST
partition.

Thoughts, Comments etc?

--
Kirk