Re: Attaching IASP to another system

I agree with your thinking but no, at least not with internal disk. As Marc mentioned you can do it with external disk but the clustering does need to be set up in advance. It's all about the O/S's knowledge of the disks. If the O/S knows about them via the cluster then how exactly they got there is not important. The SAN did it so that's good enough. With internal disk you don't have that option.

You cannot simply 'introduce the O/S' to some disks and say: "Trust me these here are an iASP" like Windows or Linux will simply 'see' a bunch of disks and bring them on line.

- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 11/5/2015 3:58 PM, Evan Harris wrote:

Hi Marc

Thanks for the response. We have done a few planned swaps with IASPs in the
same cluster, my question was more of a general one prompted by thinking
about storage. So what I am wondering is: if I know what disks/LUNs form
part of an IASP can I define that on a another system that had no previous
knowledge of it and just bring it online.

For example, I can do a conceptually similar thing by copying storage
spaces from an i-on-i guest LPAR to an other system and simply by attaching
them to some virtual scsi adapters I can get the whole system to fire up.

Can I do a similar thing with an IASP ?

For clarity I am not trying to do this as part of a HA role swap or as part
of a cluster I am just kind of curious as to whether i can (for example)
run up copies of IASPs on another system on an ad hoc basis by manipulating
the associated storage.

Hope that explains further what I am wondering about.


On Fri, Nov 6, 2015 at 8:28 AM, Marc Rauzier <marc.rauzier@xxxxxxxxx> wrote:

Le 05/11/2015 20:15, Evan Harris a écrit :

Hi all

Hello

We have been doing some lab work on PowerHA and the technologies around it

and have a question regarding IASP storage:.

Is it possible to attach an IASP to a new system and keep the contents of
the IASP intact, and if so h ow ?

If I had 3 LUNs defined in an IASP and copied that storage to 3 other LUNs
is it possible to then attach that storage as an IASP to a new system and
bring the IASP up on the different system ?

The source and destination systems must be members of the same cluster and
must be defined in the device domain. You do have to have one destination
system per target system until 7.2. There are improvments in 7.2 regarding
this sentence but I did no tested them yet.
While the target IASP is varied off, you can then use a flashcopy from the
source volumes to the target volumes and then, vary on the IASP on the
target system. PowerHA provide STRxxxSSN commands to initiate the
flashcopy. xxx is SVC for an SVC (and brothers like V7000) external
storage. xxx is ASP for DS8x00 external storage.
I am not aware of any possibility to do the same clone operation with
internal disks.

We do it every night on around 20 clusters to perform the backup to tape
operation on the target systems.

The PowerHA SystemMirror for i redbook as a chapter for this kind of
operations.

I realize there could be some application dependencies missing like user

profiles, JOBDs or whatever, but from a pure data/storage perspective is
it
possible to do what I am asking.

Yes. The administrative domain provided by PowerHA can help you to
synchronize user profiles, job descriptions, job queue definition (not the
content), and so ....
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