Paul:
The iASP lives on the same SAN as anything else does. It's just a different
way of doing it. You are using the approach I referred to as DR and it's
sufficient for 95% of my customers.
If you have the PHA toolkit from IBM you can make that switch with one
command. That handles the HMC commands needed, as well as all the work that
is done on the SAN. Almost too easy to do....
--
Jim Oberholtzer
Agile Technology Architects
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Musselman, Paul
Sent: Thursday, March 29, 2018 2:13 PM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Subject: RE: What is the difference between Flash storage and a Flash
Storage system like the V9000/V7000
The question becomes: How long can the company function without the
computer? 1 day? 6 hours? 2 hours (for an IPL of the other box)? 2
minutes?
Then you attach a price tag to each answer, and see when they say 'ouch!'
It's an insurance policy.
We have a DR system using dueling iSeries/V9000 configurations. The V9000s
keep each other in sync (using Consistency Groups because "Metro Sync" ends
up as 'synchronous' instead of 'async' when the buffers fill up). No iASPs.
So the copy is a system that needs an IPL to be usable. That's about 2
hours (including futzing around, wringing hands), but that's acceptable to
the company.
We can make a flash copy of the DR copy and IPL that for auditing purposes--
showing that the live system lives on the DR box and is usable.
iASP is nice, but where does the iASP live? If it's in the data center and
the data center goes out, or the iASP dies, there goes your HA solution.
You still need an off-site copy, either on tape or in a 2nd box.
Paul E Musselman
PaulMmn@xxxxxxxxxxxxx
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Jim
Oberholtzer
Sent: Thursday, March 29, 2018 2:46 PM
To: 'Midrange Systems Technical Discussion' <midrange-l@xxxxxxxxxxxx>
Subject: RE: What is the difference between Flash storage and a Flash
Storage system like the V9000/V7000
We are discussing the difference between and HA system and DR system, the
difference being simple. The HA box uses iASP and can do a switch in
minutes. The DR solution replicates the entire partition (the target
partition is powered off) and in the event of an unplanned switch has to IPL
and recover from an unplanned outage.
A planned switch would be to initiate the switch (use the IBM Rochester
services toolkit to make it one command) and the local system powers off,
then starts the remote box, and reverses the flow of data. No rebuild.
ALL systems should be fully journaled and that minimizes the Database
Consistency since the system simply uses the journals to get everything up.
Done properly an unplanned outage can be recovered from with relative ease
and minimal downtime.
Since the SAN is doing the replication that moves that workload off of the
Power Systems box saving quite a bit there.
--
Jim Oberholtzer
Agile Technology Architects
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