LVS Basic Learning __ Load Balancing

Technology mainly involved ';

IP load Balancing: Is the most efficient in the implementation of load balancing technology, including three technologies, Vs/nat Vs/yun, VS/DR

including Nat a group of servers to constitute a high-performance, highly available virtual server, the problem exists, network services asymmetric problems.

IP tunneling Technology: Vs/yun, VS/DR (direct router)

Three types of structures used in clusters:

A, Load scheduler (balancer), B, server pool, C, shared storage, which provides a shared storage area for the server, makes it easy for the server pool to have the same content and provide the same services. Usually by the database, the network file system, the Distributed File system composition, these three different storage ways differ in, the server node dynamic update data puts in the database system, simultaneously the database maintains the concurrent access data the consistency, the static data resides in the network File System (NFS/CIFS), However, the scalability of the network system is limited, in general, Nfs/cifs Server can only support 3-6 busy server nodes, for large-scale cluster system, you can consider the use of distributed file systems, such as Afs,gfs,coda,intermezzo, Distributed file systems provide shared storage for a variety of servers, and they access distributed files as well as access to a stupid brother's file system, while distributed file systems are scalable and available.

Distributed lock Manager: When an application on a different server accesses the same file on the Distributed file system at the same time, the application's access violation needs to be resolved in order for the resource to be in a consistent state.

Network Address Transformation: a technology that belongs to the access Wan, is a conversion technology that converts private (reserved) addresses into legitimate IP addresses, and it is widely used in various types of Internet access and various

Type of network, NAT can not only solve the problem of insufficient IP address can also effectively avoid attacks from outside the network, hide and protect the internal computer.

In the practical application, NAT is mainly used to realize the problem of accessing the private network to the public network, which replaces more private IP addresses with a small number of public IP, will help to alleviate the exhaustion of the available IP address.

RFC 1918 reserves Three IP address blocks for private networks, as follows:
Class A: 10.0.0.0~10.255.255.255
Class B: 172.16.0.0~172.31.255.255
Class C: 192.168.0.0~192.168.255.255
The above three addresses are not allocated on the Internet and can therefore be freely used within a company or enterprise without applying to an ISP or registry.
Technical background of network address translation

Implementation: There are three kinds of ways: static conversion: Dynamic NAT, Dynamically transform: Dynamics, Port Multiplexing,

Static conversion means that the private IP address of the internal network is converted to the public IP address, the IP address is a pair of, is invariable, a private IP address is converted to a public IP address only,

Port multiplexing: Pat,port Port is the port conversion of the source port that changes the outgoing data.

Realize: