Re: Power HA

I would not go 4TB of internal Disk with PowerHA. Yes Internal works and I do it. Setting up a pair today actually. But for any significant amount of disk SAN is better in most ways.

You get Flashcopy availability. This enables you to back up at the remote site while replication remains active or create training environments that are quickly refreshable, just two example.

During a roll swap you can keep replication active even while you do maintenance to the Power System. Thus it stays current. This is a big deal because when you are murphy you want to fail things when you are vulnerable, it's what you do.

The CPU load and importantly the Network load is off your IBM i as the SAN handles that.

AND once you get the final disk pricing you'll usually find that well before 4TB of disk the SAN is coming out cheaper anyway.

Not knocking PowerHA on internal disk just pointing out its limitations!

- Larry "DrFranken" Bolhuis

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

On 3/1/2017 12:20 PM, Tsvetan Marinov wrote:

But you know you can use PowerHA with internal disks too. As long as you don't have more than 4TB for each LPAR you should be fine.
Software replication solutions tend to give you a lower RPO than PowerHA and they require every day maintenance, compared to PowerHA.

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On Wed, Mar 1, 2017 at 3:36 PM +0000, "Steinmetz, Paul" <PSteinmetz@xxxxxxxxxx> wrote:










Rob,

I did something similar back in Jan 2015.

I replaced 18 1794 177gb SFF--2 SSD with 13 ESOP 775gb SFF-3 SSD.
The 177 were about to come off 3 year warranty.

We also needed more space.

The 775 were about the same price I paid for the 177 3 years earlier.
And the BP sold my 177, got some money back for those.

Three years will be up in Jan 2018, will be time for another SSD swap, or maybe a new box by then.

These were all internal, Production LPAR.
I also did this without a reload, including the load source.
Used movdta and copy load source utility.

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Rob Berendt
Sent: Wednesday, March 01, 2017 10:15 AM
To: Midrange Systems Technical Discussion
Subject: RE: Power HA

My boss only gave me, verbally, the end figure. No mention of the SAN type was made.


Rob Berendt