ePrism User Guide - EdgeWave

HALO (High Availability and Load Optimization)
HALO Overview
HALO (High Availability Load Optimization), is the fail-safe clustering architecture for high
availability for the ePrism Email Security Appliance. HALO enables two or more ePrism systems
to act as a single logical unit for processing a mail stream while providing load balancing and high
availability benefits.
HALO ensures that mail messages are never lost due to security vulnerabilities or individual system
failures. The clustering architecture is illustrated in the following diagram.
Cluster Management
The ePrism systems participating in the cluster will be grouped together by connecting a network
interface to a separate network called the Cluster Network. The ePrism systems will communicate
clustering information with each other via this network. Systems can also be added or removed
from clusters without interruption to mail services. It is recommended that all systems in the
cluster should be running on the same platform (e.g., ePrism M3000), and that the cluster network be
separated from the main production network.
One system is configured to be the Cluster Console which is the "master" system where all cluster
administration and configuration will be performed. When an ePrism system is added to the
cluster, its configuration will automatically be synchronized with the Cluster Console. Any changes
to the configuration on the Cluster Console will also be replicated to every cluster member.
The ePrism cluster will be treated as a logical unit for processing mail and system configuration.
Note: Clustered systems do not support ePrism Mail Client/WebMail, and Secure
WebMail proxy.
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