Below is a list of projects with complementary goals to those of the Linux-HA project.
The Linux Virtual Server project (LVS includes Network Address Translation, tunneling, and direct routing). LVS recommends using the Linux-HA "heartbeat" code. There is a document describing how to configure them together.
HA-OSCAR High Availability Open Source Cluster Application Resources is an open source project aims to provide a combined power of High Availability and Performance Computing solution. Our goal is to enhance a Beowulf cluster system for mission critical grade applications. To achieve high availability, component redundancy is adopted in HA OSCAR cluster to eliminate this single point of failure. HA-OSCAR incorporates a self-healing mechanism; failure detection & recovery, automatic failover and fail-back. (HA-OSCAR uses Linux-HA technology)
High Availability RAID from Software RAID HOWTO
The Linux Scalability Project. The primary goal of this research is to improve the scalability and robustness of the Linux operating system to support greater network server workloads more reliably. We are specifically interested in single-system scalability, performance, and reliability of network server infrastructure products running on Linux, such as LDAP directory servers, IMAP electronic mail servers, and web servers, among others.
OSCAR Open Source Cluster Application Resources. The OSCAR is a snapshot of the best known methods for building, programming, and using clusters. It will hopefully bring some form of uniformity to clusters, foster commercial versions of the cluster software, and make clusters more broadly acceptable.
The Linux/IR project
Linux Enterprise Computing overview
IP Channel Bonding for Linux. Channel bonding is the technique of using more than one ethernet link to increase bandwidth and availability on IP networks. See IpFailoverChannelBonding for how to use this with Linux-HA.