Server cluster definition
A server cluster is a group of linked servers, working together closely and deployed to improve performance and/or availability over that provided by a single server. Clusters could be categorized as:
- High-availability clusters
- High-availability clusters (also known as Failover Clusters) are implemented primarily for the purpose of improving the availability of the WordFrame web applications which the cluster provides. They operate by having redundant nodes, which are then used to provide services when system components fail. The most common size for this cluster is two nodes, which is the minimum requirement to provide redundancy. In WordFrame Integra, such clusters are built by installing the same application software on more then one webserver and connecting them to a single database. To achieve automatic failover a request distribution device or a load balancer with failover settings is required.
- Load-balancing clusters
- Load-balancing is when multiple servers are linked together to share the job execution workload, cache and request handling. Logically, from the user side, they are multiple machines, but function as a single virtual machine. Requests initiated from the user are managed and distributed among all the standalone computers to form a cluster. This results in balanced computational processing among different machines, which will improve theperformance of the cluster system. In WordFrame this will achieve the way the high-availability cluster works, but the load balancer settings are set to distribute evenly the incoming user requests to all cluster members. The background job distribution is handled by WordFrame Integra Platform and done automatically.
In WordFrame Integra, we categorize further the previous cluster types, based on their function:
- Front-end cluster
- Manages and serves all user generated web requests, generates and handles webpages and the presentation of the data. They have the WordFrame Integra application installed, unlike the back-end cluster, which is purely Microsoft SQL database cluster.
- Backend cluster
- This is a pure Microsoft SQL database cluster according to the specifications, technology and implementations of Microsoft. They are formed not by using WordFrame Integra platform, but by MS SQL and MS Windows server products working together. They provide high scalability and availability. They store and manage all the data.
Last edited by Boz Zashev on 29 Sep 2010 | Rev. 1 |
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