1. Field of the Invention
The present invention relates to the field of network servers and more specifically to load balancing for network servers with multiple blades.
2. Description of the Related Art
A network server is computer or device on a network that manages network resources such as network traffic. A blade server comprises a server architecture that houses multiple server modules (i.e., blades) in a single chassis. Blade servers are widely used in datacenters to save space and improve system management. Either self-standing or rack mounted, the chassis in such an architecture provides the power supply, and each blade has its own Central Processing Unit (CPU), memory and hard disk. A blade is a single circuit board populated with components such as processors, memory, and network connections that are usually found on multiple boards. A blade is typically designed to slide into an existing server. Blades are more cost-efficient, smaller and consume less power than traditional box-based servers.
Blade servers generally provide their own management systems and may include a network or storage switch. With enterprise-class blade servers, disk storage is external, and the blades are diskless. This approach allows for more efficient failover because applications are not tied to specific hardware and a particular instance of the operating system. The blades are anonymous and interchangeable.
An increasing problem for networks that are connected to the Internet is a Denial of Service (DoS) attack. A DoS attack is an assault on a network that floods it with so many additional requests that regular traffic is either slowed or completely interrupted. A DoS attack interrupts network service for some period, resulting in a condition in which the victim system can no longer respond to normal requests. Various approaches have arisen to defend against such attacks.
One approach to fending off DoS attacks is the capability of some blade servers to shield individual blades from the DoS attack by shifting workload to other resources. A multihomed blade server can monitor TCP/IP (Transmission Control Protocol/Internet Protocol) traffic and throughput and perform load balancing functions. Multihomed is used to describe a host connected to two or more networks or having two or more network addresses. For example, a network server may be connected to a serial line and a Local Area Network (LAN) or to multiple LANs. In this approach, at the server level, workload is sent to uplinks with lesser loads. The problem with this approach is that a blade may be unaware of the fact that an external uplink is loaded and will continue forwarding workload to that uplink. That is, load balancing does not occur at the blade level.
Thus, the need arises to solve the problems with the prior art above and specifically for a more efficient way to perform load balancing in a server with multiple blades.