The Linux-HA (High-Availability Linux) project provides a

high-availability High availability (HA) is a characteristic of a system which aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period. Modernization has resulted in an increased reliance on these systems. Fo ...

( clustering) solution for

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

, FreeBSD, OpenBSD, Solaris and

Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and la ...

which promotes

reliability Reliability, reliable, or unreliable may refer to: Science, technology, and mathematics Computing * Data reliability (disambiguation), a property of some disk arrays in computer storage * High availability * Reliability (computer networking), a ...

availability In reliability engineering, the term availability has the following meanings: * The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at ...

, and serviceability (RAS).Alan Robertson ''The Evolution of The LinuxHA project''. IBM Linux Technology Center, 201

/ref> The project's main software product is Heartbeat, a GNU General Public License, GPL-licensed portable cluster management program for

high-availability cluster High-availability clusters (also known as HA clusters, fail-over clusters) are groups of computers that support server applications that can be reliably utilized with a minimum amount of down-time. They operate by using high availability softwa ...

ing. Its most important features are: * no fixed maximum number of nodes - Heartbeat can be used to build large clusters as well as very simple ones * resource monitoring: resources can be automatically restarted or moved to another node on failure * fencing mechanism to remove failed nodes from the cluster * sophisticated policy-based resource management, resource inter-dependencies and constraints * time-based rules allow for different policies depending on time * several resource scripts (for Apache, IBM Db2, Oracle, PostgreSQL etc.) included *

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

for configuring, controlling and monitoring resources and nodes

History

The project originated from a mailing list started in November 1997. Eventually Harald Milz wrote an odd sort of Linux-HA HOWTO. Unlike most HOWTOs, this was not about how to configure or use existing software, it was a collection of HA techniques which one could use if one were to write HA software for Linux. Alan Robertson was inspired by this description and thought that he could perhaps write some of the software for the project to act as a sort of initial seed crystal to help jump start the project. He got this initial software running on 18 March 1998. He created the first web site for the project on 19 October 1998, and the first version of the software was released on 15 November 1998. The first production customer of the software was Rudy Pawul of ISO-NE. The ISO-NE web site went into production in the second half of 1999. At this point, the project was limited to two nodes and very simple takeover semantics, and no resource monitoring. This was cured with version 2 of the software, which added n-node clusters, resource monitoring, dependencies, and policies. Version 2.0.0 came out on 29 July 2005. This release represented another important milestone as it was the first version where very large contributions (in terms of code size) were made by the Linux-HA community at large. This series of releases brought the project to a level of feature parity-or-superiority with respect to commercial HA software. After version 2.1.4, the cluster resource manager component (responsible for starting and stopping resources and monitoring resource and node failure) was split off into a separate project called Pacemaker, and the resource agents and other "glue" infrastructure were moved to separate packages. Thus with the version 3 series, the name ''Heartbeat'' should be used for the cluster messaging layer only.

Notes

References

* *

External links

Linux-HA website

Linux-HA fact sheet - provides a detailed list of features

archives of Linux-HA's main mailing list

Pacemaker website
{{DEFAULTSORT:Linux-Ha Free system software Parallel computing High-availability cluster computing 1999 software

History

See also

Notes

References

External links