A blade server is a compact, self-contained server that consists of core processing components that fit into an enclosure with other blade servers.

A single blade may consist of hot-plug hard-drives, memory, network cards, input/output cards and integrated lights-out remote management. The modular design of the blade server helps to optimize server performance and reduce energy costs.

Blade servers are designed to overcome the space and energy restrictions of a typical data center environment.

Some of the benefits of blade servers include:

Storage area network (SAN) is a secure high-speed data transfer network that provides access to consolidated block-level storage. An SAN makes a network of storage devices accessible to multiple servers. SAN devices appear to servers as attached drives, eliminating traditional network bottlenecks

SAN solutions are available as two types:

• Fiber Channel (FC): Storage and servers are connected via a high-speed network of interconnected fiber channel switches. This is used for mission-critical applications where uninterrupted data access is required.
• Internet Small Computer System Interface (iSCSI) Protocol: This infrastructure gives the flexibility of a low-cost IP network.

Both provide advantages based on business requirements.

The advantages of SAN include:

Network attached storage (NAS) is a dedicated server, also referred to as an appliance, used for file storage and sharing. NAS is a hard drive attached to a network, used for storage and accessed through an assigned network address. It acts as a server for file sharing but does not allow other services (like emails or authentication). It allows the addition of more storage space to available networks even when the system is shutdown during maintenance.

NAS is a complete system designed for heavy network systems, which may be processing millions of transactions per minute. NAS provides a widely supported storage system for any organization requiring a reliable network system

Direct Attached Storage (DAS) is a dedicated digital storage device attached directly to a server or PC via a cable. Advanced Technology Attachment (ATA), Serial Advanced Technology Attachment (SATA), eSATA, Small Computer System Interface (SCSI), Serial Attached SCSI (SAS), and Fiber Channel are the main protocols used for DAS connections.

DAS creates data islands, because data cannot be shared with other servers.

A typical DAS device may be an internal or external hard disk drive. Depending on data criticality, disk drives may be protected with different levels of Redundant Array of Independent (or Inexpensive) Disks (RAID). Modern DAS systems include integrated disk array controllers with advanced functionalities

DAS advantages include: