Apache HTTP Server Version 2.3

Apache > HTTP Server > Documentation > Version 2.3 > Modules

# Apache Module mod_lbmethod_bybusyness

Available Languages: en

Description: | Pending Request Counting load balancer scheduler algorithm for `mod_proxy_balancer`
Status: | Extension
Module Identifier: | lbmethod_bybusyness_module
Source File: | mod_lbmethod_bybusyness.c
Compatibility: | Split off from `mod_proxy_balancer` in 2.3

### Summary

This document is still under development.

### Directives

This module provides no directives.

### Topics

- Pending Request Counting Algorithm

### See also

- `mod_proxy`
- `mod_proxy_balancer`

## Pending Request Counting Algorithm

Enabled via `lbmethod=bybusyness`, this scheduler keeps track of how many requests each worker is assigned at present. A new request is automatically assigned to the worker with the lowest number of active requests. This is useful in the case of workers that queue incoming requests independently of Apache, to ensure that queue length stays even and a request is always given to the worker most likely to service it fastest.

In the case of multiple least-busy workers, the statistics (and weightings) used by the Request Counting method are used to break the tie. Over time, the distribution of work will come to resemble that characteristic of `byrequests`.

Available Languages: en