zrep provides an easy-to-use program to manage zfs filesystem replication and failover. No configuration files are required. The program is developed under Solaris, but may work with any up to date zfs implementation. The executable is a single script. Initialization does a full data copy, but subsequent syncs are incrementals. It uses internal locking to make sure there is no danger of overlap if you just shove it in cron to run every minute. Design target is more "near-time replication", since the sync can be run every minute or more. However, it could conceivably be used for "backup" purposes as well.
rstash is a server and client for transferring files over a network into file drop boxes on the server. It is primarily aimed at transferring things such as backup files from one host to another without opening up complete shell accounts, NFS, FTP, or other full file transfer mechanisms. The server has a set of boxes into which the client can put named files in a write-only fashion. No access to any portions of the server's file system outside the configured drop boxes is permitted.
Hot Copy creates an instant point-in-time snapshot of any block device while the system is running without interrupting applications or requiring the use of LVM. As block level changes are made to the real device, hot copy makes a backup copy of the changed block. The changed blocks are efficiently stored in unused space on your hard disk. These stored changed blocks maintain a point-in-time snapshot and space is only needed when you make changes to the real device. You can even write to your snapshots.
The dsnapshot script provides a high-level interface to the Linux Logical Volume Manager. It uses its block-level snapshot support to create directory snapshots. In contrast to block-level snapshots, directory snapshots resemble the file system layer. Thus, you can snapshot any directory that is on a logical volume without worrying about the actual logical volumes, mount points, and paths.
Openduckbill is a simple command line backup tool for Linux. It is capable of monitoring files and directories marked for backup for any changes, and transferring these changes either to a local backup directory, a remote NFS exported partition, or a remote SSH server using rsync. It can either maintain an exact copy of the source at the backup destination, or maintain both current and previous versions of the source at the backup destination.
Vbackup is a modular backup utility that can be used to perform full or incremental system backups. It consists of a set of scripts that can be used to create backups using tar and xfsdump. It can also make backups of PostgreSQL, MySQL, and LDAP databases, keep a copy of the boot record, the partition table, or the LVM configuration, encrypt archives using x509 certificates, and back up the Debian package list and the RPM database. It can store the backups in a local or remote directory using either NFS or SCP. It is modular, and can be extended to perform other functions as well.