Load
Balancing Cluster
With the explosive growth of the Internet and its increasingly important role in our lives, the traffic on the Internet is increasing dramatically, which has been growing at over 100% annual rate. The workload on the servers is increasing rapidly so that servers will be easily overloaded for a short time, especially for a popular web site. To overcome the overloading problem of the servers, there are two solutions. One is the single server solution, i.e. to upgrade the server to a higher performance server, but it will soon be overloaded when requests increases so that we have to upgrade it again, the upgrading process is complex and the cost is high. The other is the multiple server solution, i.e. to build a scalable network service system on a cluster of servers. When load increases, we can simply add a new server or more into cluster to meet the increasing requests, and commodity server is of highest performance/cost ratio. Therefore, it is more scalable and more cost-effective to build server cluster system for network services.
Following services can be load balanced
Apache
MySQL (replication slaves)
FTP
SSH
And more
Fail-over
Cluster
These days, high availability is in demand. No one wants any services they offer to be unreachable, especially since that downtime will almost undoubtably cost them money. High Availability Linux clusters offers the solution to this need for a lack of downtime.
Fail-over cluster is set of two servers
acting as master and slave server
In case of primary craches or not available
slave will become master and
continue serving requests, as soon as master
server back it again takes
control from slave and slave become standby.
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