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Re: An area for operations growth - Storage Area Nets in MANS
- From: Petri Helenius
- Date: Mon May 19 06:35:37 2003
Although I agree that storage networking as a backup/tandem resiliency
operation makes a lot of sense,
it does not come anywhere nearly "free" because the assumptions made
there require flawless software.
If you always synchronize your systems you'll also blow them both out
when you hit a software issue
and as most of the audience is painfully aware, they are not infrequent
enough to count out of the equation.
So you need to keep track how to re-synchornize after an
upgrade/failure/etc. With a large stream of
updated data on the system keeping the state difference becomes
expensive quickly. (unless you are going
to re-sync everything after a failure, and then you'll be vulnerable
until that's completed)
Pointers to perfect SAN solutions appreciated.
Pete
Gordon Cook wrote:
Roxane Googin is usually ahead of the competition in spotting trends
in data net use. here is what has has to say about enterprise use of
MANs.
COOK Report: Where are the metro area networks going?
Googin: Probably the killer application for the MAN is grid computing
and storage area networks. A lot of people think the driver for
broadband access to the home is going to be multi-media. People, when
they think about next generation networks, think home use. But this
is never where the money has been. And no phone company is ever going
to build the infrastructure.
Although these new real time applica tions will clearly send more data
over the network, the real killer application is going to be remote
storage and synchronous storage. Synchronous storage means that you
have two large servers doing the exact same thing at the exact same
time in two different locations.
COOK Report: Like a decentralized disk array?
Googin: Yes. The backbone has to be incredibly fast because you
cannot complete a transaction until you have acknowledgments from both
disk drives. This will happen. Probably this year. What they are
already doing is taking fiber channel and putting that on a Cienna
Core Director optical switch port. Half of the ports being sold on
the Core Director now are fiber channel. They aren't even Ethernet.
And this is used for storage area nets (SANs). These are corporate
MANs and will have nothing to do with sales to service providers.
They are bypass business services where the storage arrays may not be
more than a kilometer or two apart. These SANs are backing up
continuously terabytes of data. We are talking huge applications that
will use every bit of access to every bit of capacity they can get.
COOK Report: Is 9/11 a motivation for this?
Googin: Partly. Not only that but the whole paradigm of the real time
organization will drive it. It used to be that your server had its
own storage. It was a "stove pipe" connected to the CPU. Now as soon
as you decouple that "stove pipe," you can put it anywhere. What they
are finding is that if they have two of them that are mirrored in real
time and place remotely that they do not have to do as much management
of resources.
COOK Report: Then forget the disaster back up and recovery
operations? Those are the next to be marked for extinction?
Googin: Oh yes. It is so elegant. The new architecture cannot be
supported on direct attached storage. It must move off the server and
it is doing so. If you have to go through a server to get to the
storage, it simply doesn't work. Storage can't become just a utility
until you move it off the server. The MAN will be backing up
terabytes of data regularly and in real time. Disaster recovery, in
real time, comes for "free".
For more detail please see
Fiber & Wireless as First Mile Technology - Fiber Business Models &
Architecture http://cookreport.com/12.04-06.shtml
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