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About Mirror Servers

A Coveo Mirror server hosts a copy of the master index located on the Coveo Master server. A Mirror server allows distributing queries between servers to speed up the querying process and to provide failover capability.

The process to add a Mirror server to a Coveo instance involves the following steps:

  1. Installing the Coveo Mirror components on a dedicated server (see Installing CES Mirror Components).

  2. Configure the Coveo Master server to recognize and synchronize its index with remote Mirror server (see Adding a Mirror Server).

  3. Configuring one or more Front-End servers to send queries to the new mirror server and to other available Back-End servers (see Coveo .NET Front-End First Time Setup).

Mirror server facts

  • The Coveo Master server hosts the master index. In the Administration Tool, the Master index is named the Default mirror.

  • A Mirror server contains a copy of the master index, and therefore also duplicates the slice configuration of the Master server.

  • A Master server sends index changes to the Mirror servers following its update schedules.

  • The Coveo administrator can also schedule Mirror server updates, for example to off-peak hours.

  • One Mirror server exclusively serving queries can typically respond to 25 queries per second (QPS), which can be adequate for several thousand concurrent users.

  • Mirror servers provide a failover capability when the Master server and one or more Mirrors are configured in a network load-balancing (NLB) cluster. As long as one server is up and running, the system can return results to respond to incoming queries.

  • You consider adding one or more Mirror servers:

    • When the query responses time increases notably (above one second) during peak usage because the Master server is busy with the multiple Coveo processes.

    • When you want to have query serving failover capability.

    • When you want to completely free the Master server from the query serving task.

      Tip: You can add two or more Mirror servers in an NLB cluster, excluding the master server from the cluster, and sending all queries from the Front-End servers to the NLB cluster address (see Configuring Coveo Servers in a Network Load-Balancing Cluster).

A network load-balanced (NLB) cluster including the Master server and two Mirror servers.
The Coveo Master server
Up to two index slices of the Master server
A first Coveo Mirror server with its duplicate Master server index slices
A second Coveo Mirror server with its duplicate Master server index slices
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