Cloud Drive Sync : Can I Use File Syncing as a Backup?
  
Can I Use File Syncing as a Backup?
File sync is sometimes confused with file backup, but is very different. File sync does not protect data. It is not a substitute for file backup, because:
Sync is bidirectional. For example, files deleted in the cloud are automatically deleted locally. This is not a desirable feature for backup, which should produce a stable, read-only copy of your data.
Sync is continuous. Backup should run at scheduled intervals and preserve an accurate point-in-time snapshot of your data.
Sync should not transfer locked files. Backup should transfer files which are locked by applications.
When using sync gateway mode, sync allows you to share file access with other users. Backup should protect your data from other users.
Sync supports standard files and documents. Backup should support applications, such as databases, in addition to standard documents.