I currently have a draytek 2820N along with 2 internet connections, currently one is performing backup duties and if one drops out the other picks up.
One thing i wish to do though is use 1 connection 99% of the time but divert specific traffic through the other.

The specific type of traffic is dropbox through the second internet connection

Do i need to use some form of load balancing or static routing? Or within the dropbox config it allows for proxy to be setup can i set an internal proxy which then diverts all traffic from this proxy to the second internet connection?

Any help would be greatly appreciated!

With that setup you'll ideally need to have one of the WAN connections specified as the default route (which you can do in telnet by entering "ip route default wan1" or wan2), after that you can specify load balance policies under the WAN menu to force specific traffic through a WAN connection.
In the load balance policies if you leave "auto failover" ticked it'll go through the other WAN if needed when the WAN connection specified fails.

Voodle wrote: In the load balance policies if you leave "auto failover" ticked it'll go through the other WAN if needed when the WAN connection specified fails.

Can't see this specific bit.

Updated to latest firmware and this option appeared.

I could not seem to restrict dropbox traffic so instead i pretty much did all the standard ports and sent them through the normal connection then did the "default" as the backup. Therefore solving the issue.