If your security settings allow cached credentials on end-user devices, you can assign nearly-seamless failover and high-availability capabilities to Connect Tunnel clients and Mobile Connect SSL VPN Tunnel clients. You can do this even if the SMA appliances are in different locations (and therefore do not share an internal network).
To enable cached credentials
Navigate to Managed Appliances > Configure.
Click Define Policy.
Click on the community for a realm.
Click the Access Methods tab.
In the Tunnel (IP Protocol) section, click Configure.
Scroll down to and expand the Tunnel Client Options section.
In the Cached Credentials section, configure how you want the cached credentials to operate.
For more information on using cached credentials, refer to the SMA 12.4.1 Administration Guide.