Discover How 3CX Failover Works

January 31, 2019
3CX Failovers are an integral part of 3CX SAAS reliability and one of the reasons SenSys Technology recommend them to our clients. Find our more

Businesses in Ireland lose, on average, 2 days of business annually, due to IT / Comms downtime.

3CX is a SAAS (software as a service) which can be deployed in the cloud.  SenSys Technology recommends the server offering as we can provide a full 24/7 Proactive monitoring solution to ensure that there is no downtime.

Server - 3CX

From a server hardware redundancy point of view, the server will come with redundant power supply units as standard, RAID 1 on the operating system which mirrors the hard drives and the hard drives will be enterprise specification with the option for a 4-hour response time on replacements of failures. If there is a significant amount of storage required for call recording, RAID 1 can also be used. RAID 1 allows for 1 hard drive failure without compromising the system. A battery backup on the RAID controller card will prevent data loss in the event of a sudden power cut where an uninterruptible power source (UPS) has run out of power.


The 3CX system will typically sit behind a firewall and will use port forwarding to allow connectivity to the VOIP provider, for remote connections using the softphone and access to the management console. For internet failover the firewall would need to be able to support multiple Wide Area Network (WAN) links, which typically should be supplied by two different providers and preferably using different technologies such as WAN1 is fixed line broadband and WAN 2 is supplied by a wireless provider.

In cases where only one broadband provider can be used, it will be possible to keep several public switched telephone network (PSTN) lines for failover. The PSTN lines can be converted to IP and added to 3CX, this will allow calls to be made outbound (caller ID will be different) and received as the main number used can be diverted to the PSTN numbers if there is an outage. This can be done automatically on the VOIP providers side.

3CX License options

The 3CX enterprise license allows for failover to a server on a different site with updates to the fully qualified domain name (FQDN) within 5 minutes. This is used in the event of complete hardware failure which would be rare due to the measures taken with hardware redundancy. The active server will be backed up every 24 hours to Google drive which the passive server will have access to. A heartbeat will be maintained between the passive and active server and if this is broken the passive server will automatically take over as the primary once the DNS entries are updated in 5 minutes.

3cx failover diagram

The four key elements required for successful operations are:

  • Electricity
  • Server
  • Internet
  • IP redundant multiple data centre

Our aim, at SenSys Technology, is to ensure customers enjoy 24/7 functionality and reliability from their systems.  SenSys is a 3CX Partner.

If you are interested in having a chat about the savings which your business can make by installing a 3CX phone system, please get in touch:

Phone 01 9060553 or Freephone: 1800 815 683


Click on the links to view our case studies on the Pillo Hotel. Telecoms System, The Vienna Woods Hotel cloud managed wi-fi system or Business phone system installed in

Read our article on VoIP & Discover Why You Should Switch here

Interested in finding out how SenSys Technology can converge your business systems onto one smart platform?