Exclude based on remote file system #847
Description
A great many sites use rsync for backup of remote systems. However, these remote systems often use data from other remote systems via NFS, Samba, SSHFS, or similar protocols. Also, they mount the same information in multiple places due to bind mounts, or may wish to exclude all tmpfs mounts. System administrators that believe in backing up entire systems (not just selected app-specific data) often sweep up these redundant copies of data, increasing the backup run time, network bandwidth demand, and storage requirements.
Such sysadmins currently address this by manually creating custom "exclude" lists for each system they back-up, listing all the items that specific system should exclude. These exclude lists are static while the systems they cover may change over time. In another scenario, it's common to clone a system to create a new system, and the exclude lists don't automatically follow these new systems, either.
A better solution would be for rsync to support the exclusion of remote file systems by type. An "--exclude-fstype" option (e.g. "--exclude-fstype=nfs4,cifs,tmpfs") would be a tremendous improvement. Adding a new NFS mount would not require the system administrator to remember to manually update an exclude list. A cloned system would also automatically be treated by local standards regarding whether to include remote-mounts. Optionally, a "remote" keyword (e.g. "--exclude-ftsype=remote") as an alias for "--excludefs-type=nfs,nfs4,cifs,sshfs,..." would avoid a sysadmin overlooking some specific remote file system mount.
Similarly, an "--exclude-bind" or "--no-bind" would also eliminate a lot of redundant backups.
Please accept this as a feature request to add an "--exclude-fstype" and a "--no-bind" option. The remote rsync client is the only component of the backup process that can see the remote file system types, and implementing this feature would help a great many people.
Thank you for considering this feature request.