Hot Standby Overview

The high reliability and high availability performance of server plays a vital role in an application system. Once the key system is down, it may lead to significant losses in data and a variety of issues. Yeastar provides a Hot Standby solution, which can provide high system availability and prevent you from the unnecessary business loss caused by unexpected server failure.

Requirements and restrictions

Two identical Yeastar P-Series PBX Systems are required to set up a Hot Standby pair, and the servers in the Hot Standby pair must meet the following requirements.
Item Requirement
Product Model The two PBXs are the same model.
Hardware Installation The two PBXs have identical hardware installation (The same expansion board and telephony module are installed in the same position and slot).
Plan Hot Standby can be used without additionally subscribing to a plan.
Note: Make sure that you subscribe to the desired plan for the PBX that will act as the Primary Server in the Hot Standby pair. When the Secondary Server takes over the system, the features included in the plan will automatically be available on the Secondary Server.
Firmware The firmware version of the two PBXs are the same ( or later).
Network The two PBXs use the same Internet Protocol, both assigned with static IP addresses, and are located in the same LAN subnet.
  • Yeastar P-Series PBX System supports to set up Hot Standby pair that are located in the same LAN subnet.
  • Hot Standby only works for LAN port.
    Note: If the Ethernet mode of the PBX is Dual, set the default interface to LAN port (Path: System > Network > Basic Settings).
  • Hot Standby doesn't work in VPN network.
  • Hot Standby is NOT supported on FXS module.

Operation Mechanism

The following content describes the operation mechanism of the Hot Standby feature.

Set up Hot Standby pair

The solution consists of two PBXs (a Primary Server and a Secondary Server) with the same hardware and firmware. The Primary Server works in "active" state while the Secondary Server works in "standby" state and cannot be configured.

The two PBXs share a virtual IP address, which always points to the active PBX. In this way, PBX administrator can access and operate the PBX system via the virtual IP address directly.

For more information about the configuration, see Set up Hot Standby Pair.


Under normal operating, the Secondary Server sends heartbeat keep-alive packets to the Primary Server periodically, and synchronizes the data and configuration from the Primary Server in real-time so that the two devices contain identical information.

Once the Primary Server goes down, the Secondary Server will take over the PBX system automatically if it doesn't receive any response from the Primary Server in a certain time. In this way, the system will continue to run.

Also, the system will send Hot Standby related event notifications to the notification contacts concerned, informing them to repair the Primary Server as soon as possible.

Take over the PBX system manually

After you have repaired the Primary Server, you need to manually set up the Primary Server to synchronize data and take over the PBX system from Secondary Server.

For more information about the configuration, see Primary Server Takes over the System from Secondary Server.