Installation guide

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Device Manager Guide, Cisco ACE 4700 Series Application Control Engine Appliance
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Chapter 6 Configuring Real Servers and Server Farms
Server Load Balancing Overview
The ACE Appliance Device Manager allows you to configure load balancing using:
• Virtual servers—See Configuring Virtual Servers, page 5-2.
• Real servers—See Configuring Real Servers, page 6-5.
• Dynamic Workload Scaling—See Configuring Dynamic Workload Scaling, page 6-14.
• Server farms—See Configuring Server Farms, page 6-18.
• Sticky groups—See Configuring Sticky Groups, page 7-11.
• Parameter maps—See Configuring Parameter Maps, page 8-1.
For information about SLB as configured and performed by the ACE appliance, see the following topics:
• Configuring Virtual Servers, page 5-2
• Load-Balancing Predictors, page 6-2
• Real Servers, page 6-3
• Dynamic Workload Scaling Overview, page 6-4
• Server Farms, page 6-5
• Configuring Health Monitoring, page 6-39
• TCL Scripts, page 6-40
• Configuring Stickiness, page 7-1
Load-Balancing Predictors
The ACE appliance uses the following predictors to select the best server to satisfy a client request:
• Hash Address—Selects the server using a hash value based on either the source or destination IP
address, or both. Use these predictors for firewall load balancing (FWLB).
Note FWLB allows you to scale firewall protection by distributing traffic across multiple firewalls on
a per-connection basis. All packets belonging to a particular connection must go through the
same firewall. The firewall then allows or denies transmission of individual packets across its
interfaces. For more information about configuring FWLB on the ACE appliance, see the Server
Load-Balancing Guide, Cisco ACE Application Control Engine.
• Hash Content— Selects the server by using a hash value based on the specified content string of the
HTTP packet body
• Hash Cookie—Selects the server using a hash value based on a cookie name.
• Hash Secondary Cookie—The ACE selects the server by using the hash value based on the specified
cookie name in the URL query string, not the cookie header.
• Hash Header—Selects the server using a hash value based on the HTTP header name.
• Hash Layer4—Selects the server using a Layer 4 generic protocol load-balancing method.
• Hash URL—Selects the server using a hash value based on the requested URL.You can specify a
beginning pattern and an ending pattern to match in the URL. Use this predictor method to
load-balance cache servers. Cache servers perform better with the URL hash method because you
can divide the contents of the caches evenly if the traffic is random enough. In a redundant