Servers power the software that
will help your business thrive and your team to collaborate, but what do you
need? We decipher the jargon and highlight the key features you need to look for.
Sharing files, running important
applications for your team, managing printers - these are all tasks that can
waste your business a lot of time if you haven't put the right tools in place.
Chances are, when your business
started there were only a small number of people and sharing files was pretty
easy. You'd either email them to each other or pop them on a USB stick and hand
them across the office - what we used to call SneakerNet in the old days. If
you got a little more tech savvy you might have even shared folders on each
other's PCs so you could access files.
But as the number of people in the
business grows, the job of sharing information gets harder. At some point it
makes sense to designate one computer as a hub from which everyone else
accesses shared information. That's what a server does - it acts as a central
point that can be accessed by lots of people for accessing IT services.
Key Server
Terminology Explained
Like any technical area, buying
servers means that you need to get your head around a bunch of jargon.
Racks and Towers: If you're planning to invest in several pieces
of business technology, such as storage, network switches and storage then
you'll need to decide between either a tower or a rack-mounted server. Towers
look like big desktop PCs. Rack-mounted servers are designed to be held by a
couple of screws and a mounting system in a standard computer rack.
For a small business starting out,
a tower is probably a slightly less expensive option as you can probably get
away with non-rack-mounted network and storage equipment. But if your business
is growing a rack-mounted server is a good option as it will take up less space
and can be stored in a secure rack, away from prying eyes and hands.
Hot-Swappable Parts: One of the things the separates servers from
regular computers is that many of the components are designed to be removed and
replaced without turning the server off and interrupting your business. The
main components that are made with this in mind are disk drives and power
supplies. This capability is called "hot swappable". It works as the
server is made with multiple hard drives that are configured so that data is
automatically written to multiple places. If one drive fails, your data is safe
on another.
Similarly, having multiple power
supplies means that if one power supply fails the load can be picked up by the
second one. Being hot-swappable means you can switch a bad unit for a good one
without impacting operations.
How Much
Memory And Storage Does A Business Server Need?
Calculating how much memory and
storage your server will need can be a daunting task. For the purpose of this
exercise, we're going to assume that the server will be carrying out several
functions. These are:
- File
server (for sharing documents and other files)
- Print
server (for managing a couple of networked office printers)
- Finance
system
- Key
customer management system (this is the main system that your business
uses for running the business)
- Email
server (for corporate email)
For each of these, you'll need to
allocate three main things:
1. Storage
2. Processor
3. Memory
So, you might end up with a matrix
like this:
|
Storage
|
Processor
|
Memory
|
|
|
File server
|
4TB
|
2 cores
|
4GB
|
|
Print server
|
50GB
|
1 core
|
2GB
|
|
Finance system
|
1TB
|
2 cores
|
2GB
|
|
Customer management system
|
2TB
|
2 cores
|
4GB
|
|
Email server
|
2TB
|
2 cores
|
2GB
|
|
Totals (with some overhead)
|
10TB
|
10 cores
|
16GB
|
(We'll be covering storage
in more detail in Chapter 2.)
With processors, it's important to
understand that it comes down to much more than just the clock speed — the
number usually tacked onto the processor name that's given in GHz.
The modern processor is really a
number of CPUs joined together. So, a quad-core processor is really like four
CPUs that have been melded together to act as one. So, your buying decision
will be based on the number of cores and the clock speed together.
So, if you decide that you need 12
processor cores to run all the applications and services your business needs
then what you're looking for is a server that holds enough servers to cover the
number of processor cores you need.
Although it's possible to add
processors to a server later, to accommodate future needs, you're probably
better off allowing for some overhead now. So, although out current need is for
ten processor cores, we'd most likely, look for a server with 12 or 16 cores.
When you're adding a new
processor, you'll need to ensure that the second, or subsequent processor is
the same specification as the one you already have.
Or, you'll need to remove the
existing processor and add new, alike processors to the system.
With memory, upgrading later is
easier but you still need to ensure that you have enough for your current needs
and anything you anticipate in the immediate future.
The good news is that most vendors
maintain stock of common upgradable components so you can buy equipment today
with confidence that you'll be able to upgrade in future as needed rather than
investing in hardware before you need it.
In the old days, you'd probably
end up buying separate servers for each of those functions, or combine a couple
of the less demanding applications on one box in order to save a few dollars.
Today, you can buy a single server to do all those tasks. They key to this is
virtualisation.
Operating
System And Virtualisation Options
Virtualisation isn’t a new
technology but it is one that has matured and reached commercial acceptance
over the last decade or so. Here's how it works.
In the past, the accepted best
practice was that each server was allocated a specific task. For example, you
would run email from its own server. You wouldn’t double up functions so that
the one server would run your email and finance system.
There were two reasons for this.
Firstly, if the server failed, you'd lose access to two critical functions.
Secondly, the amount of processing power available wasn't sufficient for both
functions to run effectively on the one server.
Both of these problems have been
overcome through better, more reliable hardware, and by Moore's Law. Processing
power is no longer a bottleneck for most applications.
Virtualisation takes one powerful
computer and, through the use of software called a hypervisor, allows you to
create virtualised computers that are allocated their own slice of the
available memory, processor and storage capacity.
Virtualisation and Hypervisors
Think of it like this. Imagine
your server is made of a series of layers.
At the bottom is the hardware -
the processors, memory and storage. Sitting above those is the hypervisor. It
acts as a broker that distributes the hardware resources to the virtual servers
that sit in the next layer up. Each of those servers, although running on the
same server, is isolated from all the others. So, if one virtual server needs
to be restarted or has a problem, it won’t affect the others.
The hypervisor is a barebones
operating system that carries out a single task - the allocation of hardware to
virtual servers. This can be dynamic.
Let's say you decided to set up a
server with three virtual servers running on it. Each separate virtual server required
two CPU cores. That means you need access to six CPU cores. However, the
reality is that none of the applications will be using 100% of their allocated
server cores at the same time. The hypervisor can allocate the resources, to a
maximum of two cores per server, dynamically. If this is done efficiently, you
might be able to get away with a physical server that has just four CPU cores.
It also means you can run multiple
operating systems on the one physical server. So, if you have applications that
require Windows Server, you can run those alongside applications that require a
Linux server.
As well as being a really
efficient way to get the most out of your server hardware, virtualisation
offers you lots of flexibility without having to invest in multiple physical
servers.
Which Hypervisor?
Choosing a hypervisor for your
server can be a confusing task. The two main players in the hypervisor market
are VMware's vSphere and Microsoft's Hyper-V. There are also some other options
such as Citrix XenServer and Oracle VM.
The two main players, vSphere and
Hyper-V, have different strengths and weaknesses.
If you are running Microsoft
server applications exclusively and have an existing licensing agreement with
Microsoft then the scales will probably tip in Hyper-V's favour. As well as
being optimised for Windows Server, Hyper-V licensing costs may be included in
your current server licensing arrangements, or added at a reasonable cost.
If you're running a more diverse
set of applications and need to support different server operating systems such
as a Linux-based OS, then you may find vSphere is a better fit. However, it's
possible this will cost more.
Another thing to bear in mind is
that if you decide to run all your applications from a single physical server
you are creating a single point of failure in your systems. One of the great
features of modern hypervisors is that you can replicate entire virtual servers
across different physical hosts easily. Although the hardware cost goes up, you
can increase the confidence that a single hardware failure won’t stop the
business.
Operating Systems
Within businesses, the most
popular server operating system is Windows Server. Now over a decade old and in
its sixth iteration (if we ignore the old days of Windows NT Server), Windows
Server is increasingly popular and is the most use operating system in
businesses.
Access to skilled professionals
and technicians when it comes to deploying Windows-based servers and
applications is plentiful. All of the major hardware manufacturers and
suppliers have established relationships with channel partners to assist with
not only setting up a server and your preferred hypervisor but with deploying
applications and getting your business productive as quickly as possible.
If you prefer to take the open
source road, then you're most likely going to be looking at Red Hat, SUSE or
Ubuntu for the operating systems you run.
Checklist:
Buying A Server
- Make
a list of what will need to run on the server
- Determine
the operating system, processor, memory and storage needs for each
application Choose which hypervisor will best suit your environment
- Design
a solution that adequately mitigates the risk of bringing your business to
a halt of a single component or device fails
- Talk
to a hardware suppliers to determine the best match of hardware and
software for your budget
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