filesync synchronizes a source tree of files with a destination tree; the trees typically reside on separate systems. It performs copies, moves and deletions on the destination tree so that it matches the source tree.
IMPORTANT: the two trees must be scanned in advance with filemetatool, to ensure that all file hashes are up to date (see https://github.com/ddirect/filemetatool for more info).
filesync uses the filemeta library which currently requires Linux and file systems with extended attributes (e.g. EXT4).
filesync -do OPERATION [OPTION]... -base FILE_TREE
filesync is run in server mode on the source system and as client on the destination one.
In both modes, filesync first scans the tree and creates an in-memory data structure (called "db") containing information about the tree of files, including all file hashes.
In server mode (serv operation), it then listens and serves connections (TCP or Unix sockets) coming from client instances.
In client mode, it connects to a filesync server, requests the remote db and computes the operations which would be needed to make the local file system match the remote one. It then either shows the operations (diff or fulldiff operations) or it performs them right away (recv operation).
filesync attempts to avoid copying the file data from the remote system: if a file with the same hash exists locally, a hard link to it is created instead of performing a copy. Similarly, if two files with the same hash exist on the remote system but not on the local one, a single copy is performed and a hard link to the first file is created for the second one.
- deduplication: if the destination tree is empty,
filesynccopies the source tree deduplicating any file (it creates multiple hard links to the same inode for files containing the same data) - synchronization: if the destination tree contains a backup of the files of the source tree taken at an earlier time,
filesyncefficiently updates the backup minimizing the number of needed operations
filesync -bind :6001 -do serve -base <source_tree>
Starts filesync in server mode on TCP port 6001, for source_tree.
filesync -do recv -remote <remote_host>:6001 -base <destination_tree>
Starts filesync in client mode and synchronizes the tree on remote_host, port 6001 onto destination_tree.