Understanding types of server form factors between tower, rack and blade

 Tower Server:

These are upright, free-standing units that contain all traditional server components: hard disks, motherboards and central processing units (CPUs), networking, cabling, power and so on. You commonly add a hard drive to a tower server for direct attached storage (DAS).
Tower servers generally require more floor space than bladed environments or rack-mounted servers, and offer less scalability by design.
Tower servers are ideal for small, remote or branch office environments, and offer maximum in-chassis flexibility and all-inclusive server/storage solutions.

 Rack Server:

These are complete servers specially designed for ultra-compact vertical arrangement within a standardized
19-inch mounting rack or cabinet.
Rack-mounted models have expansion slots, known as mezzanine slots, for adding network interface cards (NICs) or Fibre Channel host bus adapter (HBA) cards. This configuration uses floor space efficiently, and offers centralized cable and server management. In addition, a rack server configuration increases infrastructure scalability by letting you add servers as needed, and connect to external storage, such as a network attached storage (NAS) or storage area network (SAN).
It's important to note that relative to server blades and enclosures, rack servers are more limited in the number of new drives and memory you can install.
Rack servers are generally designed to work as a logical and cohesive whole but without the tight integration found with server blades, which makes rack servers more flexible in some situations. In addition, you can run servers from different manufacturers in the same rack unit because the servers don't share proprietary components.
Rack servers are ideal for data centers and use with external storage. They offer maximum computing power in a space-saving design.

 Blade Server:

These are small form factor servers housed in blade enclosures, which are designed for modularity and high-density footprints (enabling you to fit more servers into a smaller space). A blade enclosure includes server blades and room for storage, in addition to many shared components—power, cooling and ventilation, networking and other interconnects—all controlled by an integrated management system.
Blade infrastructures generally require less rack space than rack-mounted servers. Blade enclosures also use less power per server because of shared power and cooling, which equates to less heat output and lower cooling costs.
Some blade infrastructure enclosures can increase the number of servers up to 60 percent.
Blade servers are ideal for data centers and use with external storage, and offer maximum computing power in space, power and cooling saving designs.

 

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