Fake: Redundant Server Switch  
   Fake has been designed to switch in backup servers on a LAN.
   http://www.us.vergenet.net/linux/fake/

Linux Virtual Server Project  
   A virtual server is a highly scalable and highly available server built on a cluster of real servers. The architecture of the cluster is transparent to end users, and the users see only a single virtual server.
   http://www.LinuxVirtualServer.org/

Conditional Execution Based on Host Availability  
   The Answer Guy 32: Conditional Execution Based on Host Availability.
   http://www.linuxdoc.org/LDP/LG/issue32/tag_ping.html

Jungo: GO-HotSwap  
   Add CompactPCI hot-swap capabilities to: Linux / Embedded Linux, Solaris, VxWorks, Windows9x, Windows2000, Windows NT, and Windows NT- Embedded.
   http://www.jungo.com/cpci.html

Linux-HA Project  
   Root page for High-Availability Linux Project; goal: Provide a high-availability (clustering) solution for Linux which promotes reliability, availability, and serviceability (RAS) through a community development effort.
   http://linux-ha.org/

failoverd  
   Software to provide rudimentary failover capability for Linux
   http://www.ps-ax.com/failoverd/

Linux High Availability HOWTO  
   Linux High Availability HOWTO
   http://metalab.unc.edu/pub/Linux/ALPHA/linux-ha/High-Availability-HOWTO.html

Process Monitor HOW-TO for Linux  
   Process Monitor HOW-TO for Linux, to monitor and restart important processes on your system.
   http://www.linuxdoc.org/HOWTO/Process-Monitor-HOWTO.html

drbd  
   Drbd is a block device which is designed to build high availability clusters. This is done by mirroring a whole block device via (a dedicated) network. You could see it as a network raid 1.
   http://www.complang.tuwien.ac.at/reisner/drbd/

Lemuria.org - Heart Software  
   A basic framework for a high-availability implementation. It exchanges and updates the status of all nodes within the cluster, so that a crash can be immediately noticed and appropriate action be taken.
   http://www.lemuria.org/Heart/

MOSIX  
   MOSIX for Linux is a cluster-enablement technology that provides transparent process migration between nodes in a cluster. Migration is pre-emptive and transaparent to the user; processes run remotely via distributed system calls.
   http://www.mosix.cs.huji.ac.il/

Software-RAID HOWTO: High Availability RAID  
   High Availability RAID from Software RAID HOWTO.
   http://www.linas.org/linux/Software-RAID/Software-RAID-9.html

A High-Availability Cluster for Linux  
   A High-Availability Cluster for Linux A Linux Journal Article by Phil Lewis.
   http://www2.linuxjournal.com/cgi-bin/frames.pl/lj-issues/issue64/3247.html

H.A. Technical Solutions  
   They make reliable high availability, data replication and load balancing software solutions including H.A. Clusters, H.A. EchoStream and H.A. Fulcrum.
   http://www.tech-sol.com