Directory is a ZODB storage which uses ordinary files and directories to store revisions of ZODB objects; one file per revision per object.

The following features differentiate DirectoryStorage from other storages:

1. Constant memory usage, even during packing. With the right filesystem, I believe this makes DirectoryStorage the most scalable storage available today.
2. A very simple file format. Your data is not locked away inside an unfamiliar, opaque database.
3. Use familiar filesystem tools for maintaining the database. For example:
   • Take an incremental backup using tar.
   • Make crucial persistent objects immutable using file permissions.
   • Replication using rsync.
4. Designed for fault tolerance.

For more information see DirectoryStorage on SourceForge.