---
title:  High Availability for Client-Server Communication
---

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The client provides reliable event messaging from cache server to client to prevent data loss during server failover operations. High availability is implemented in the cache server and is configured in the client.

See server documentation at [Configuring Highly Available Servers](<%=vars.serverman%>/developing/events/configuring_highly_available_servers.html) for details about configuring a server for high availability.

-   **[Configuring Clients for High Availability](configuring-nc-ha.html)**

    Configure high availability by setting the pool attribute `subscription-redundancy` to the number of copies maintained.

-   **[Sending Periodic Acknowledgment](sending-periodic-ack.html)**

    Servers use periodic acknowledgment to reduce the likelihood of duplicate notifications, and to reduce resource usage.