SysAdmin: Linux has shown a lot of growth in the area of data-centric, high-availability clustering. Most admins are already familiar with computational clusters, known loosely as Beowulf clusters, which are implemented in the form of MPI, PVM, LAM, MOSIX, and other process-sharing and process-distributing technologies. There are also "Web service clusters", such as those distributed in years past by TurboLinux and others. These were typically groups of similarly configured servers that used DNS and round-robin IP address tricks to give the illusion of Web server high-availability to end users.

Cohesive operation between the nodes, however, was still only achieved through a shared-storage medium, such as Fibre Channel or shared SCSI, which are prohibitively expensive for small businesses, or proprietary cluster hardware and software, which is also prohibitively expensive. A database engine that serves a Web cluster must still itself be clustered to achieve true high-availability. Application-level high-availability tools (such as the MySQL database engine) that transparently replicate themselves between servers, are also being used to provide some level of redundancy.

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