Highlights
- Improved reliability
- Faster failover performance
- Minimal impact on CPU performance
- Minimal impact on bandwidth
Marketing description
The original version of SonicOS Enhanced provided a basic High Availability feature where a Backup firewall assumes the interface IP addresses of the configured interfaces when the Primary unit fails. Upon failover, layer 2 broadcasts are issued (ARP) to inform the network that the IP addresses are now owned by the Backup unit. All pre-existing network connections must be rebuilt. For example, Telnet and FTP sessions must be re-established and VPN tunnels must be renegotiated.
Stateful High Availability (SHA) provides dramatically improved failover performance. The Primary and Backup appliances are continuously synchronized so that the Backup can seamlessly assume all network responsibilities if the Primary appliance fails, with no interruptions to existing network connections.
Product Features
- Improved reliability
By synchronizing most critical network connection information, Stateful High Availability prevents down time and dropped connections in case of appliance failure. - Faster failover performance
By maintaining continuous synchronization between the Primary and Backup appliances, Stateful High Availability enables the Backup appliance to take over in case of a failure with virtually no down time or loss of network connections. - Minimal impact on CPU performance
Typically less than 1% usage. - Minimal impact on bandwidth
Transmission of synchronization data is throttled so as not interfere with other data.
