only 30 mins of data retention... even AWS gives you 2 weeks at 5min resolution for free (albeit only stuff the hypervisor can measure because they don't run an agent, so no RAM etc).
AWS doesn't give you any minutes of data retention if you aren't paying them by the hour for the server. You can use Longview on any server, it does not have to be hosted by Linode.
If you host with Linode you already get access to graphs going back a year for CPU / Network and IO. Longview is in addition to that offering.