Rsync is a completely appropriate solution here. @jellefoks' answer covers most of how to do it, I'd like to add that I use rsync to backup a 20+ TB NAS over 1GB to another NAS and it takes roughly 1.5 hours to do this nightly. So using 100MB it will obviously be slower but given your data set sizes it should be completely acceptable.

The only caveat with rsync is if the nature of the data is such that it's a lot of files, then it will obviously take longer, than if they're fewer larger files. There are some optimizations you can make with rsync to tell it to compare files based on timestamp and size vs. a checksum to improve it's performance.

Lastly I'd like to suggest using BackupPC. It gives you the option of using a variety of methods to backup, (Samba, rsync, etc.) but it's true value is the web based reports. These are extremely useful in seeing if a backup ran and how long it took.

Rsync is a completely appropriate solution here. @jellefoks' answer covers most of how to do it, I'd like to add that I use rsync to backup a 20+ TB NAS over 1GB to another NAS and it takes roughly 1.5 hours to do this nightly. So using 100MB it will obviously be slower but given your data set sizes it should be completely acceptable.

The only caveat with rsync is if the nature of the data is such that it's a lot of files, then it will obviously take longer, than if they're fewer larger files. There are some optimizations you can make with rsync to tell it to compare files based on timestamp and size vs. a checksum to improve it's performance.

Lastly I'd like to suggest using BackupPC. It gives you the option of using a variety of methods to backup, (Samba, rsync, etc.) but it's true value is the web based reports. These are extremely useful in seeing if a backup ran and how long it took.