What does 'Non-persistent' mean with Heroku's Redis To Go Nano plan?

I recently signed up for Heroku's Redis To Go https://addons.heroku.com/redistogo. For now, I'm using the free Nano plan, which says:

5 MB Redis Instance
1 Database
Non-persistent
No Backups
10 Connections

I get what 'No Backups' etc. mean, but can't find any info on what is 'Non-persistent'? Does it mean the data is wiped out every time I deploy? Daily? Every now and then? When Heroku crashes?

Solution

Non-persistent means that your data will disappear if a restart of your instance is needed
e.g. Server issues caused by AWS usually involve instance restarts.

The other plans all provide AOF persistance and daily snapshot RDB backups of your data.
The Direct plans are 30% cheaper and you get more features.

More info on persistence and backups