Can I back up my Database for safety?
For how long will Frihost host my website? 1 or 2 years?
Can I have 2 subdomain?
Can I upgrade my space to 1000MB?
you can backup everything you want, just don't do it too often(once a day is a lot) as it uses a lot of resources to backup something big.
Frihost will host you as long as you keep posting on the forums, look at the faq to see how exactly this is calculated.
You can have one subdomain from frihost, and create as much sub-subdomains under that as you want. Also you can buy your own domain name (not at frihost) and use that (and create subdomains on that if you want). You can add as many domains as you want.
We only provide one free hosting package.