Re: IBM Bolsters Disaster Recovery With GDR For IBM i

https://www.itjungle.com/2017/05/03/ibm-bolsters-disaster-
recovery-gdr-ibm/
IBM Bolsters Disaster Recovery With GDR For IBM i
May 3, 2017 Alex Woodie<https://www.itjungle.com/author/alex-woodie/>
IBM next month plans to start selling a new disaster recovery product to
IBM i shops. Called Geographically Dispersed Resiliency, or GDR, the new
offering is designed to give companies an easy and affordable way to
recover production IBM i LPARs on remote machines. IBM's resiliency guru
Steve Finnes gives IT Jungle the lowdown on the new tech.
GDR provides DR protection by essentially taking a production logical
partition (LPAR), also called a virtual machine (VM), from one IBM i server
and restarting it on another IBM i server. The VMs involved in a GDR switch
must be stored on a storage area network (SAN) server - either an IBM<
http://www.ibm.com> DS8000, SVC, or Storwize server or an EMC<
http://www.emc.com> array - and the two arrays can be geographically
dispersed (as you may have guessed from the name).
Finnes says GDR serves a need for an affordable and easy-to-use DR
solution. "It's very, very simple and yet it gets the job done," Finnes
says. "One person can literally run a DR restart operation with this
technology."
Operators work with GDR from their PowerVC consoles, where they issue
commands to an AIX LPAR called K-SYS. "The operator issues a command to
K-SYS, which stands for control system, that says 'I want to restart at
site two.' K-SYS takes over and conducts an orderly shutdown of the source
and brings it up on the target side," Finnes says. "The whole process is
very simple."
[https://e5ce463uma323hyvrr4xumqs-wpengine.netdna-ssl.com/wp-
content/uploads/2017/01/tfh050317-story01-fig01.png]
GDR provides VM restart capability through the K-SYS command (graphic
courtesy IBM)
The software, which has been available for AIX and Linux customers since
last year, is similar in some respects to VMware<http://www.vmware.com>'s
popular Site Recovery Manager (SRM) product, which many X86 shops use to
recover production environments in the event of actual disasters and to
conduct DR readiness checks.
Testing DR processes has been a big point of emphasis in the business
resiliency field, and so DR readiness is a big part of GDR, according to
Finnes. "Typically what people are doing in the DR site is testing. They
need to test to demonstrate they can do a DR operation," he says.
"Hopefully nobody ever actually has to use the disaster recovery. We
wouldn't wish that on anybody. But the ultimate purpose of any DR solution
is if I did have a disaster, I can actually go and recover."
The GDR product, which becomes available for IBM i on June 23, borrows
concepts and technology from other IBM offerings that many IBM i shops are
familiar with, including Live Partition Mobility (LPM) and PowerHA.
GDR is "conceptually a first cousin [to LPM]. The basis is essentially the
same," Finnes says. The big difference, he says, is that there is no
rebooting the VM with LPM.
"With GDR, I'm essentially going through an IPL process," Finnes says.
"I'm actually creating those VMs on the fly, bringing it all up into the
processor complex, loading up the environment, and resuming production on
that target box."
While GDR is separate and distinct from PowerHA, it does borrow data
replication technologies from PowerHA. Specifically, it uses the Metro
Mirror and Global Mirror replication protocols to actually transmit data
from the storage array in the production environment to the storage array
in the backup environment. For EMC environments, GDR uses the Symmetrix
Remote Data Facility (SRDF) replication protocol.
A GDR customer would use the synchronous Metro Mirror protocol when the
production and backup systems are located on the same campus or city, and
use the asynchronous Global Mirror protocol when the sites are distantly
located. SRDF supports both synchronous and asynchronous modes.
In some respects, recovering an IBM i environment with GDR is similar to
recovering an IBM i environment with tape. "That's essentially what it is.
You're really rebooting or IPL'ing that VM into the target site," Finnes
says. "You do a scratch install, boot up everything off of this image."
Because of the need in GDR to wind down the VM on the production box in a
methodical manner and then spin it up in the new environment, the recovery
takes a bit of time. "It's going to take longer [than a high availability
role swap] because you're going through essentially an abnormal IPL
process," Finnes says, adding that the time it takes to complete the IPL
will vary according to the database size and other factors.
In terms of recovery point objective (RPO), the GDR solution will be very
aggressive in recovering all of your work, or nearly all of it. If GDR is
configured with Metro Mirror or synchronous SRDF data replication, the RPO
could be as low as zero, meaning that as soon as a transaction is written
to the local machine (or the local storage server, since that's where the
VM actually lives), then it's protected with GDR.
The recovery time objective (RTO) is not nearly as aggressive with GDR,
which is what you would expect with a DR solution. Because a GDR recovery
is essentially an abnormal IPL of the production IBM i system, it could
take some time for the customer to get back up and running with GDR, as
Finnes previously mentioned.
These characteristics make GDR a good potential solution for customers who
are looking for a DR solution. "There are people who want a DR solution. I
think it's going to be interesting for those people because it's relatively
inexpensive and it's very simple to use," Finnes says.
The one caveat to GDR is that it does require the user to be invested in
IBM or EMC storage arrays, and be somewhat capable in AIX technologies like
K-SYS and the virtual I/O server (VIOS). Because many of the IBM i shops
that have bigger IBM SANs, like the DS8000, they are likely to be using
PowerHA - and because PowerHA already includes comprehensive high
availability and DR capabilities - that limits the potential market for GDR
among those bigger IBM i shops.
"The DS8000 customers are really, truly mission critical, the 'who's who'
of American industry," Finnes says. "There's no reason for them to do this.
They already have a compressive HA and DR setup within the cluster so I
don't envision the DS8000 clients doing this."
On the other hand, smaller IBM i shops running the popular Storwize arrays
are not as likely to be invested in PowerHA, and therefore could be good
candidates for GDR. As of June 23, the SVC storage server - which is not
nearly as popular among IBM i shops - is now supported with GDR, along with
IBM i, Storwize, and DS8000 arrays.
There is also the potential for IBM business partners to build DR as a
service (DRaaS) offerings atop an IBM storage array with GDR supplying the
replication and recovery capabilities. Finnes says he's seen a lot of DRaaS
offerings pop up recently, which makes him think there could be a good
opportunity here for GDR.
GDR potentially could reduce the software licensing costs for customers
compared to PowerHA or high availability solutions built atop logical
replication technology. Because the customer's application software is
never active on multiple machines at the same time, and the secondary
system is a true "cold" backup - as opposed to a "warm" or a "hot" backup,
which is often the case with HA or clustering technology - it could soften
the software licensing requirements for customers.
The list price for GDR is $1,020 per core for a "small processor" and
$1,575 per core for a "medium processor." Please contact IBM for
definitions on processor size.

Thank You
_____
Paul Steinmetz
IBM i Systems Administrator

Pencor Services, Inc.
462 Delaware Ave
Palmerton Pa 18071

610-826-9117 work
610-826-9188 fax
610-349-0913 cell
610-377-6012 home

psteinmetz@xxxxxxxxxx<mailto:psteinmetz@xxxxxxxxxx>
http://www.pencor.com/

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