@Vishal6
You can achieve VPN redundancy client side by modifying the XML profile to include a backup server. You'd use the AnyConnect/Secure Client VPN Profile Editor. Example:
When the primary server fails, the client will automatically try the backup server(s).
The XML profile can be uploaded to the ASA/FTD, once the user successfully connects they will download the XML profile with the new settings. Or you can deploy the XML profile using your software management solution.