Knowledge of dual-machine backup

What is dual-machine hot standby http://www.chinastor.com/a/jishu/shuangji/2011/0621205H011.html guide: What is the dual-machine hot standby technology? Dual-Machine hot standby, Standby, is a common server high-availability technology. As the name implies, a, b two machines to each other to make a backup, a break the dish b top, B break the dish a top. The typical application environment is: front-end two application servers A and B

What is dual-machine hot-standby technology? dual-Machine hot-standby, English-Standby, is a common server high-availability technology. As the name implies, a, b two machines to do each other backup, a down the top B, b down on a top.

two-machine hot standby typical application environmentis: For the critical business system, two or more servers need to complete the same function, the same service, so that they have the same configuration, each other as a backup, when a server failure, no need for manual intervention, can be another server automatically take over the work, to ensure that the system continues to operate, For high availability. There are three modes of operation for hot standby of two machines.Depending on how the two servers work, you can have three different modes of operation, namely Dual-machine master-slave mode, dual-machine interoperability mode and dual-machine duplex mode。 The following are briefly described below: Dual-Machine master-slave modeThe most common two-machine hot standby mode, which is what is commonly referred to as the Active/standby, is that the active server is in a working state while the standby server is in the monitoring readiness State. When the active server fails, the standby machine is activated by a software diagnostic or manual method to ensure that the application is fully restored to normal use in a short period of time. Typical applications are in securities funds servers or market servers. This is the current use of more than one mode, but because another server is in a state of reserve for a long time, from the computing resources to consider, there is a certain waste. dual-Machine mutual standby modeTwo relatively independent applications at the same time two machines run simultaneously, but each other is set to standby, when one server fails, another server can in a short period of time to take over the application of the failed server, so as to ensure the continuity of the application, but the performance requirements of the server is relatively high. The server configuration is relatively better. dual-Machine Duplex modeAt present, a form of cluster (cluster), active/active Two servers are active, while running the same application, to ensure the overall performance, but also to achieve load balancing and mutual backup. The Web server or FTP server is much more in this way. There are two ways to implement dual-machine hot-standbyDual-machine heat with two implementation modes, one is based on shared storage devices, the other is not shared storage devices, generally referred to as pure software mode. dual-Machine hot standby based on storage sharingis the most standard solution for dual-machine hot standby. This approach employs two (or more) servers, using a shared storage device (a disk array enclosure or a storage Area network SAN). Two servers can be hot-spare (master-slave), interoperability, duplex (parallel) and other different ways. In the course of the work, the two servers will be provided with a virtual IP address to the external service, depending on the mode of work, the service request sent to one of the servers to assume. At the same time, the server detects the state of the other server through the heartbeat line, which is often done by establishing a private network. When one server fails, another server makes a decision based on the heartbeat detection and switches to take over the service. For the user, the process is fully automated and completed in a very short period of time, thus not impacting the business. Because of the use of shared storage devices, both servers are actually using the same data, which is managed by a dual-machine or cluster software.

Knowledge of dual-machine backup