Rob,
SAN based disk is indeed the wave of the future. On very low end
POWER internal disk will continue to make sense for some time but the
bigger you are the more likely SAN will enter your future. It has
finally caught up and in many cases surpassed iBM i Internal disk
capabilities in data spreading, SSD tools, RAID maintenance, hot swap,
expandability etc. Plus with remote mirroring and flash copies etc there
is a lot to like. As integration improves such as with recent
announcements connecting V3700 and V7000 to IBM i Native this is just
more proof. Note: No Native IBM i attach on PURE, VIOS is required.
On the performance hit I believe that's really only relevant if the
VIOS is owning disk. If it does not own any disk and is merely being the
intermediary between IBM i and SAN storage then there does not appear to
be a hit. You could make it so by, well, any number of poor decisions in
the configuration and build out but not if properly designed.
A few more points:
FLEX: Looked at a lot of this stuff, talked to many, understand the
bits and pieces but so far no customer has said "It's right for me, Now."
There are two flavors, Pre-built (PureFlex) and Build your own (Flex
System.) These things are pretty complex so I would usually recommend
the first one at least be the pre-built variety with everything
integrated and configured.
Infrastructure in PURE is the whole nine yards. You get the frame,
the cooling, the power, the Ethernet network, the fiber network, the
storage (V7000), and a management node which also handles HMC(ish)
functions. Just add compute nodes to taste and load it up.
Flex will run X86 and POWER workloads based on the nodes you pick so
you can put pretty much anything in there and share the same infrastructure.
Like Blade center when it was new it looks expensive to get into a
Flex system. But it's really, well, OK it's true, it's expensive. But
that's because what you're getting is a lot. So it's not likely that
when replacing that POWER6 520 you'll choose a PureFlex System as it's
replacement. But if you have a significant amount of equipment aging
out and can plan to replace it all, or are building a new DC or location
it can make a lot of sense to look at Flex.
A few things to look out for.
Power, IBM thinks these things need a lot of power, a whole LOT of
power. And if they are loaded to the gills then yes they do. But if
you're lightly loading it, especially at first you may not need the full
power to the Flex. This is important if it appears that adding FLEX to
your DC will overload UPS and Generator (and don't forget cooling) but
once all the old stuff is gone you'll be back in the green. I've talked
to users running the system on less than half the recommended power.
Work with your BP in sizing the power connection and the number of power
supplied installed. This is very important if you are in a co-location
facility like my iInTheCloud.com setup because in those places you pay
for the power you have connected NOT the power you use. That can be a
huge price at the power level Flex has and remember it's redundant too
so at a colo facility you actually pay for both sides!
Fiber switch ports. There is a fiber switch included and licensed for
the base management node and the V7000 switch. Be very careful on
getting enough licenses for the fiber switch, it's easy to overrun the
base and find out things won't connect. Oops!
Large systems. If you are currently in a 570 or 770 or bigger then
Flex may not work for you as you are limited to 16 processor cores in a
single LPAR. They are POWER7 cores of course so that's not insignificant
Power but if you are anywhere close to 16 cores in an LPAR you're likely
not going to want to put that in Flex. That may go up in the future of
course but it's not announced, not previewed, not hinted at so don't bet
your business on that.
Drives in the Flex nodes themselves. You can put a couple in there
but doing so limits memory because now you can use only low profile
DIMMs. You probably won't want do do that and of course you'll NEVER
want any production data on those drives anyway so what would you use
them for?
Hope that gives you something to think about.
- Larry "DrFranken" Bolhuis
www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com
On 8/26/2013 9:59 AM, rob@xxxxxxxxx wrote:
We're getting one quoted.
Boss is thinking that the external storage is probably the wave of the
future. We've already some experience on guesting. Guesting on VIOS will
be much different. Hear there's some performance hit on disk that way
versus native.
Rob Berendt
midrange.com
