People who make these laws clearly don't know anything about computers. The amount of data to be stored is HUGE and it's quite a job to search the data from tapes or what ever media they use to store them.

Does the law mention how long must the data be saved? I assume at least a year.

If I were you I'd start using PGP or some similar thing and just for the fun of it sent every day a 10 MB email to myself or some fake addresses.