FWIW an option I use at my home/office is a 2u 12bay supermicro box running freenas with extra hard drives as the backup DST (Destination).

Using periodic replication on the source (also freenas/ZFS) and some Scripts I wrote using ipmi to start up the DST box-

I have the DST machine downstairs at my house And once a week for about 12 hours it auto powers up, the auto application starts and after about 12 hours shut down. (10g uplink)

So outside of 12 hours a week the machine is powered off. Not the best solution and it does have Some sec holes, but it was something cheap to backup alot of data.