Cluster-like Non-Clusters


Cluster-like Non-Clusters for SMB Messaging

Regardless of size, no business can afford to be without e-mail access
these days. Combine that with the more and more services we pile on
these mail servers and you’ve got the making of a perfect SMB disaster.
Mail servers are far more than just “mail”, they drive groupware
functionality, faxing services, calendaring, mobile device security as
well as remote document and file access. We have consolidated and built
a civilization on top of a single box yet haven’t raised our budgets
and expectations to drive what used to be spread over multiple servers,
workstations and was the sole job of a few part time employees. The
following article helps you take a look at your small business
infrastructure and realize the potential in new cluster-like features
in Microsoft Exchange 2007. . . .

Clusters are Expensive!

Yes they are. Clusters generally require very expensive shared
storage devices, storage controllers to manage either SCSI or Fiber
storage arrays, high end systems, etc. However, LCR and CCR do not
require any of this high end gear. You can use the low cost Dell
PowerEdge servers (currently Dell has a PowerEdge 440 Dual Core Intel
2.8, 2GB DDR, 160GB SATA2 on sale for $580)

To give you an example, last night I built two baseline test servers
to test LCR and CCR features of Exchange 2007. Total with shipping came
to under $900 (about $400 for each system). What’s in it?

AMD Athlon 64 X2 3800 Windsor 2.0 GHz AM2 Dual Core Processor ($91)

ECS Socket AM2 Radeon Xpress 1100 MicroATX AMD Motherboard ($58)

Wintec AMPX (2 x 1GB) 240-Pin DDR DDR2 800 (PC2 6400) Dual Channel Memory ($130)

Western Digital Caviar SE WD1600 JS 160 GB SATA 2 Drive ($53)

IN WIN Black Steel MicroATX Desktop Computer Case 240W ($50)

At the first glance this system looks very basic. Let’s look at some
of the objections. First of all – no redundant storage. Easy, not
needed. The nodes replicate data back and forth, so there is no need
for a high end storage investment. If you wanted to spend extra $53 per
node you could buy an additional hard drive and create a mirror. The
motherboard supports it. Second, only 2GB of RAM? Yes, thats the
recommended amount of RAM for the mailbox role according to Microsoft.
Not the minimum, recommended. If thats not enough, the motherboard does
support up to 16GB. You can overload the primary box with 4GB for
example and keep the failover node with far less RAM because it would
only be accessed when there is a failure. Third, motherboard and case.
This is hard to overcome so let me explain my choices. I invested in a
fairly high end processor for this setup and selected a cheaper case
becasue as a test system this will sit on my workbench. The 240W power
supply and low-footprint desktop system case will make this a cool,
quiet and small setup that I can use to get things going. For roughly
$80 more per node you can also buy a 1U Racmount case from SuperMicro that would meet your data center racking needs.

Either way, even if you bumped up the RAM, mirrored the hard drives,
bought a racked case it would cost just over $1,000 total for both
systems shipped. That is far less than what most small businesses are
investing in their primary server – why? Because we’ve been trained to
buy the most expensive solution the money can buy and budget can fit.
We’ll grow into it, right? Well, no.. no.. wrong. You see, we’ve pushed
the limits of processing very far. You get far more memory and
processing power for the buck but you still have that same lingering
issue of the single point of failure. And you’re likely spending more
for that single point of failure than you would for a redundant
configuration!

The point of this article is to shift your thinking. We have the
technology. We have the resources. We can make the disaster recovery a
lot more predictable and seamless for our clients if we’re willing to
review these new techologies, implement them and get away from “more is
better” to “more independant systems are better”. If you have a small
business you have to let go of the big-iron enterprise view of having
high end monster systems to a more distributed, more replicable smaller
systems. It will cost you less and let you sleep better at night. Hey,
take one node home with you 🙂 [Vlad Mazek – Vladville Blog]

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