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Sidewinder G2 6.1.1 Administration Guide - Glossary of Technical ...

Sidewinder G2 6.1.1 Administration Guide - Glossary of Technical ...

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HA configuration<br />

options<br />

HA configuration options<br />

In this example, all users in the internal or external network must use<br />

the cluster address (aaa.aaa.aaa.5 or bbb.bbb.bbb.5, respectively).<br />

Only system administrators should know about the other IP addresses.<br />

The same concept applies for DNS names.<br />

Tip: When configuring an existing single <strong>Sidewinder</strong> <strong>G2</strong> configuration to become an HA<br />

cluster, consider using the existing interface addresses as the cluster addresses and getting<br />

new IP addresses for the actual NICs. This lessens the impact on your users, who will not<br />

have to change their perception <strong>of</strong> the "<strong>Sidewinder</strong> <strong>G2</strong>" address.<br />

You can configure HA to perform load sharing (with both <strong>Sidewinder</strong><br />

<strong>G2</strong>s actively processing traffic) or failover (with one <strong>Sidewinder</strong> <strong>G2</strong><br />

processing traffic and the other <strong>Sidewinder</strong> <strong>G2</strong> standing by as a hot<br />

backup). The following sections discuss each HA configuration<br />

option.<br />

Load sharing HA<br />

Load sharing HA consists <strong>of</strong> two <strong>Sidewinder</strong> <strong>G2</strong>s that actively process<br />

traffic in a load sharing capacity. When a secondary is registered to an<br />

HA cluster, synchronized areas will be overwritten by the HA cluster<br />

configuration to match the primary. (To determine which areas are<br />

synchronized, see “Managing an HA cluster” on page 16-17.) Each<br />

<strong>Sidewinder</strong> <strong>G2</strong> maintains its own private (individual) address, the<br />

cluster common address for each interface (excluding the heartbeat<br />

interface), and any other alias addresses. The <strong>Sidewinder</strong> <strong>G2</strong>s are then<br />

able to coordinate traffic processing on a single shared IP address<br />

using a multicast Ethernet address to ensure that each connection<br />

(and the packets associated with that connection) is handled by the<br />

same <strong>Sidewinder</strong> <strong>G2</strong>. To configure load sharing HA, both <strong>Sidewinder</strong><br />

<strong>G2</strong>s must have the same hardware configuration (e.g., CPU speed,<br />

memory, active NICs).<br />

In a load sharing HA configuration, the primary is assigned the cluster<br />

address for the heartbeat burb as an alias, allowing it to communicate<br />

with the secondary. When the secondary or standby is brought online,<br />

it activates its interface IP addresses. The primary will then begin to<br />

"multicast" a heartbeat message. The heartbeat uses IPSec<br />

authentication (AH) to ensure that the messages are correct. The<br />

secondary “listens” for this heartbeat and sends an acknowledgement<br />

to the primary. If one <strong>of</strong> the <strong>Sidewinder</strong> <strong>G2</strong>s become unavailable (that<br />

is, a heartbeat message or acknowledgement is not received by a<br />

<strong>Sidewinder</strong> <strong>G2</strong> for the specified amount <strong>of</strong> time), the remaining<br />

<strong>Sidewinder</strong> <strong>G2</strong> takes over and assumes responsibility for processing<br />

all traffic.<br />

High Availability 16-3

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