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In today’s 24/7/365 world, web businesses cannot afford to suffer from outages for longer than minutes. Unplanned (failures) and planned (service downtime) outages can severely hamper online business.
Setting up a redundant IT structure comes at a cheaper price than the risk of even a short outage. This is especially true when considering the relatively low prices of Intel-based PCs running on Linux. And while you can budget the expense of additional hardware, software and user education, the cost of unplanned outages are impossible to estimate in advance.
The basic rule to make a high availability server is to use redundant parts where needed and affordable. Just like the basic idea behind RAID, all parts in a server are subject to being a single point of failure (SPOF). For example, a single NIC in a client/server environment is a SPOF. If a complete server fails amongst a group of several servers, and the failed server cannot be easily and quickly replaced by another server, then this server is a SPOF for the server group or cluster.
Adapter cards can be made redundant by simply doubling them within a server and making sure a backup adapter becomes active if the primary one fails. CPU, power supply etc. can be made redundant within a server too, but this typically requires special parts that are not very common in a PC environment and thus quite expensive. However, in cooperation with clustering software, Emic Application Cluster for MySQL, two or more servers in a server cluster can be set up to replace each other in case of a node outage.
Emic Application Cluster (EAC) for MySQL meets the requirements of the enterprise-level scalability and availability requirements providing:
· Load balancing of MySQL database servers
· Dynamic load balancing mode, which uses servers’ real resources
· Real-time logging & monitoring
· Fast and reliable synchronous replication
· High availability.
EAC for MySQL secures uninterrupted database services. It provides the highest level of database node and application availability. By forming virtual database entities, which can be either local or distributed, EAC eliminates the need for a shared storage device and provides failover protection while preserving all transaction ACID requirements. EAC uses clustering technology with a unique group communication replication technology, which provides the consistency of synchronous replication at the speed of asynchronous replication, with no decrease in overall performance.
All clustered databases are fully mirrored and automated fail-over or manual switchover is a transparent operation to surviving nodes. EAC for MySQL also automatically handles traffic peaks by distributing read-load among all active databases within cluster.
For more information about EAC for MySQL, visit http://www.emicnetworks.com/download/pdf/eac_mysql_whitepaper.pdf.
Or download a free evaluation version at http://www.emicnetworks.com/download/download_software.html