Ask HN: Best medium for data preservation for multiple decades archival?

Let say : - We want to preserve from 10 gigabytes to 1 terabyte of data - This is a hobby (this put constraints on both the money and time allowable on the project) - We can not / do not want to rewrite the data every 5 years on a new medium - We want the thing to be practical : durability of the data is important, but the availability (in 30 years, as a hobbyist) of the technology allowing the data retrieval is important too.

Any suggestions appreciated.