Servers are possibly the most important items on the Internet or other
networks, outside of end users. Servers provide so much of the basic
functionality needed for networks. For example,
- Web servers
- these provide the basic pages and not so basic pages associated
with the internet
- E-Mail servers
- provide the basis of e-mail
- File servers
- provide files for a large variety of purposes over the Internet
- Storage/Backup servers
- provide storage and or backup for particular information
Servers are almost always totally different than
desktop computers. They are designed with different purposes in
mind. It is almost always very important to purchase computers
that are fundamentally different from desktops when purchasing servers.
Some of the major features include
Some of the
major features of servers include
- More internal space - servers usually have more
physical space inside for devices such as hard drives and slots for
cards and CPUs.
- More CPU performance - servers can have multiple
CPUs or very fast single processors
- More upgrade options - servers usually have
more upgrade options than desktops. They are designed for
growth and allow adding things such as CPUs, RAM, disk drives and
- Rack mounts - servers should be rack mountable
to save space and improve interconnectivity
- No side access needs - servers should be
constructed so that the you only need front and back access for
making use of servers
Remember, overall performance of a server isn't
determined purely by the speed of its CPU. You also need to
consider a large variety of things such as hard drive access
speed, graphics processing and display and input/output.
It is also important to go with reputable and appropriately
priced vendors. You should also expect vendors to help you do some
of the configuring and fair amount of the service on your servers.
There are a lot of advantages to buying servers from a very
few vendors. Such environments are usually easier to maintain and
interoperability and ease of configuration should be improved.
Buying from more than one vendor can improve negotiating power during
When buying servers it is also very important to consider how repairs will
be performed. Vendors have a variety of maintenance contracts with
features associated with on-site service, response times, and warranties.
Some typical scenarios for picking the appropriate
maintenance contracts are
- host with low/medium importance - service
contracts can be for next or two day repairs. It may also be
the case that no special contract is needed because default options
- large groups of similar hosts - sometimes a site
has many of the same type of machine. In this instance it may
be worthwhile to purchase a spare parts kit so that repairs can be
performed in-house. In this case, the hosts may now require a
lower cost maintenance contract. You may also get some
economies of scale.
- controlled model selection - you might
standardize the time horizon associated with purchasing particular
servers. This can also help in terms of maintenance and spare
- critical host - this is likely to require a
service contract with a same day
- large variety of models from same vendor - in
this case you may opt for a contract that includes an on-site
technician supplied by the vendor.
- highly critical host - some vendors offer an
option that includes an on-site technician and a duplicate machine
ready to be swapped. This is often as expensive as making use
of a redundant server
There is a trade-off between how much you do your
own service while stocking your own spares and how much your rely on
a maintenance contract. Sometimes it is easier to do your own
troubleshooting. But it is also very difficult to make sure
your own staff is up to date on all the possible problems that can
happen with your current hardware.
Sometimes a sys admin discovers that an important or
maybe even critical host is not on a maintenance contract. The
following are three likely useful ways to prevent hosts from being missed
on a contract.
- Have a good inventory system to track your
acquisitions and cross reference it with your service contracts.
- Have the person responsible for making purchases
be responsible for ensuring the appropriate purchases are on
- Make sure you are aware of the warranty duration
and whether you need to add your purchase to a service contract when
it expires. The sys admin should see if the vendor can place
the purchase on a service contract when it is purchased but show a
zero dollar amount for the duration of the sales warranty.
Several other issues likely to be of significant
- Data backups
- which we will get into in much greater depth in a couple future
- Clients are seldom backed up. Hopefully,
your automated or intelligent installations and updates take care
of the major aspects of restoring a client. Even with this,
users are likely to have accumulated their own data and
information on their machines. This can be backed up in a
variety of ways.
- Servers need to be backed up quite frequently.
They are much more likely to contain mission critical information.
- Data Centers
- which we will get into in much greater depth in a couple future
- It is crucial to have things like fire and
water protection for your servers as well as other important
infrastructure items such as air conditioning. You also
likely to need power surge protection and alternative sources if
power if there are power failures.
- Operating System
- The OS doesn't need to be as uniform from
server to server as it is likely to on desktops.
- Remote Access Administration
- Servers need to be maintained remotely as much
as reasonable. You may need to be in physical contact with
the machine in some instances. But in most situations you
would rather manage them from one location.
- If configured correctly a single console server
can be used in place of many dedicated terminals for each server.
- Remote access capabilities for a server should
be a major consideration during purchase decisions.
- Mirrored Root Disks
- RAID - Redundant Array of Independent Disks can
be used to mirror the main system disk and possibly other disks.
- Server Appliances
- These are made to enhance performance for more
specifically oriented servers such as for e-mail, web, DNS and so
- They often have important specialized features.
- Redundant Power Supplies
- While hard drives are the most likely failure
point in servers, power supplies are the next.
- Each power supply should have a separate cord
- It is also fairly likely that you will want to
have a UPS - uninterruptible power supply
- Full and n+1 Redundancy
- It is often the case that you want to improve
the reliability of critical systems. Providing some
redundancy can be crucial for this.
- If there is some redundancy it is also likely
to be possible to configure things so that there is some load
- Hot Swappable Components
- Hot swap refers to the capability to remove and
replace components while the system is running.
- It is important to determine what components
can be purchased and configured as hot swappable when purchasing
- Separate Networks for
- It is often the case that it is important to
separate important administrative functions onto a separate
network for a variety of reasons.
- Information such as payroll needs to be almost
entirely inaccessible to hackers and other gate crashers.
- Certain types of administrative decision making
or competitively advantageous information is also likely to need
such additional efforts.