Duplicacy

Duplicacy is a new generation cloud-backup tool supporting most cloud-storage providers (Amazon S3, Google Cloud Storage, Microsoft Azure, Dropbox, Backblaze, and Google Drive), as well as local disks and SFTP servers (such as Mac/Linux computers or NAS boxes). Duplicacy is the only cloud-backup tool that offers all the following 7 essential features:

1. Incremental backup: only back up what has been changed
2. Full snapshot : although each backup is incremental, it must behave like a full snapshot for easy restore and deletion
3. Deduplication: identical files must be stored as one copy (file-level deduplication), and identical parts from different files must be stored as one copy (block-level deduplication)
4. Encryption: encrypt not only file contents but also file paths, sizes, times, etc.
5. Deletion: every backup can be deleted independently without affecting others
6. Concurrent access: multiple clients can back up to the same storage at the same time
7. Snapshot migration: all or selected snapshots can be migrated from one storage to another

Duplicacy also comes with an elegantly designed GUI that features one-page configuration to allow you to quickly set backup schedules and retention policies. You can also easily configure advanced options such as email notifications, automatic start on logon, and exclude/include patterns. Duplicacy is $20 per year per computer for personal use. You can find complete pricing options here.