Apache HTTP Server Version 2.4

Apache > HTTP Server > Documentation > Version 2.4 > Modules

# Apache Module mod_lbmethod_heartbeat

Description: | Heartbeat Traffic Counting load balancer scheduler algorithm for `mod_proxy_balancer`
Status: | Experimental
Module Identifier: | lbmethod_heartbeat_module
Source File: | mod_lbmethod_heartbeat.c
Compatibility: | Available in version 2.3 and later

### Summary

`lbmethod=heartbeat` uses the services of `mod_heartmonitor` to balance between origin servers that are providing heartbeat info via the `mod_heartbeat` module.

This modules load balancing algorithm favors servers with more ready (idle) capacity over time, but does not select the server with the most ready capacity every time. Servers that have 0 active clients are penalized, with the assumption that they are not fully initialized.

### Directives

### Bugfix checklist

- httpd changelog
- Known issues
- Report a bug

### See also

- `mod_proxy`
- `mod_proxy_balancer`
- `mod_heartbeat`
- `mod_heartmonitor`

## HeartbeatStorage Directive

Description: | Path to read heartbeat data
Syntax: | `HeartbeatStorage file-path`
Default: | `HeartbeatStorage logs/hb.dat`
Context: | server config
Status: | Experimental
Module: | mod_lbmethod_heartbeat

The `HeartbeatStorage` directive specifies the path to read heartbeat data. This flat-file is used only when `mod_slotmem_shm` is not loaded.