Tower Servers:
This is
the normal boxes (in appearance) you would have seen in Visio Diagrams. Of
course they are very powerful & have bundled software tools to manage them.
The problem with Tower Severs is the space they occupy, management personnel
they require, and cost of operating them (power, network, etc.).
Rack Servers:
This is servers
mounted inside a Rack (something like we normally use to manage our letters,
office files, etc.) Major Racks available out there adhere to an IEEE standard
and are measured in rack units or “U’s” (each U is 19” wide and 1.75” tall). So
a rack server size is typically in multiplication of these “U’s”. Motivation
here is to scale vertically than horizontally with more compact physical
servers. In addition to this, there are many other electronic devices which
adhere to this IEEE standard for instance – Rack Consoles, SAN devices, Power
Backup devices, etc. Advantage being that you can fix them into rack as well
along with your servers. Not to mention that the hardware vendors (Dell, HP,
IBM, etc.) provide additional software tools that help you effectively manage
these servers and in some case the supported devices also.
Blade Servers:
This is an additional
level of innovation on top of Rack Servers. Blade Servers are typically placed
inside a blade enclosure, and together they form a blade system. A Blade system
normally meets the IEEE standard of Rack Units, which means that the entire
Blade system can be placed inside the rack along with other electronic
equipments. The benefits of blade enclosure includes hot plugging (normally
blade servers have a handle attached to them, for transferring them in and out
of the blade enclosure – it’s an easy way of identifying them) and stripped
modular design (e.g. shared network ports, power connections, switches, etc.).
For instance the hardware we ordered allows us to pack 16 blade servers inside
a 10U space. blade system and SAN storage. All these boils down to further
space reduction, cost savings (power, administration staff) & easy
management. Bundle this with Virtualization and you have a very powerful
infrastructure at your disposal.
