Installation guide

CHAPTER

6-1

Device Manager Guide, Cisco ACE 4700 Series Application Control Engine Appliance

OL-26645-02

Configuring Real Servers and Server Farms

This chapter provides an overview of server load balancing and procedures for configuring real servers

and server farms for load balancing on an ACE appliance.

Note When you use the ACE CLI to configure named objects (such as a real server, virtual server, parameter

map, class map, health probe, and so on), consider that the Device Manager (DM) supports object names

with an alphanumeric string of 1 to 64 characters, which can include the following special characters:

underscore (_), hyphen (-), dot (.), and asterisk (*). Spaces are not allowed.

If you use the ACE CLI to configure a named object with special characters that the DM does not

support, you may not be able to configure the ACE using DM.

This chpater contains the following sections:

• Server Load Balancing Overview, page 6-1

• Configuring Real Servers, page 6-5

• Managing Real Servers, page 6-9

• Configuring Dynamic Workload Scaling, page 6-14

• Configuring Server Farms, page 6-18

• Configuring Health Monitoring, page 6-39

• Configuring Secure KAL-AP, page 6-70

Server Load Balancing Overview

Server load balancing (SLB) is the process of deciding to which server a load-balancing device should

send a client request for service. For example, a client request can consist of an HTTP GET for a Web

page or an FTP GET to download a file. The job of the load balancer is to select the server that can

successfully fulfill the client request and do so in the shortest amount of time without overloading either

the server or the server farm as a whole.

Depending on the load-balancing algorithm or predictor that you configure, the ACE appliance performs

a series of checks and calculations to determine the server that can best service each client request. The

ACE appliance bases server selection on several factors, including the server with the fewest

connections with respect to load, source or destination address, cookies, URLs, or HTTP headers.