That volume is huge. Unless you take 420 GB of memory cards, the laptop is not going to be your backup, it is going to be your primary copy.

This leaves you with a choice of media for your actual backup:

• Cloud storage is unfeasible because transferring 30+ GB takes more than a day with most services and in most part of the world even with the best internet connection possible.
• The easiest would be to get a portable hard-drive. If you can afford it, get an SSD because it is much more sturdy. One drop and a standard hard-drive is dead.
• The most reliable though is to use optical disks. At 30 GB that would fit in a double-layer Blu-Ray (or 4 DVD-DL). This makes it easy to make your backups in duplicate.

The advantage of optical disks is that they have no value, unlike your laptop and portable storage, so that are not a target for thieves (just do not leave them in the laptop or camera bag) and the best is to mail a copy to yourself every few days. This is the only easy way to get both duplication and distribution of data. The downside is the time to burn. A single-layer Blu-Ray takes 1 hour to burn plus an extra hour to verify integrity on my machine and my source data is on an ultra-fast SSD.

Yes, I am paranoid too about data loss. With 30 GB daily, I would be even more paranoid!