I suppose it a common way to preserve multiple generations of backup copy of your important data. To preserve them as much as possible, archiving and compressing the backup copy is one way. But there is another way to save the storage: hard-linking. The basic idea is to share the identical files between different generations of backup copy with hard links. If the target data consist of normal files, rsnapshot does most of the hard-linking management automatically. But I recently encountered the problem with the database files managed by daemon processes. Because they are supposed to be changed asynchronously, the consistency of th オプション eir copy taken with the cp command is not guaranteed. Because this kind of problems is often aware in the design of the daemon processes, special backup methods are provided to export the consistent backup copy. For example, Subversion provides "svnadmin hotcopy" subcommand, and Trac provides "trac-admin hotcopy...