What About A File System That Uses Snapshots?

equitir asks: "The file system scene for Linux is now all about journaling. While this is good and necessary, I'd like to ask if anyone is working on snapshot capabilities for any of the file systems available. Is it possible? Should it be done? Is there someone already working on something like this?" (Read More)

"I'm referring to what Network-Appliances are doing: at set times the top-level inodes are replicated but kept pointing to the hierarchy (i.e. the file system gets a new entry point). New inodes and blocks are only allocated and pointed-to for changes. This keeps a large number of entry points within the file system, representing the state of the file system at the times the snapshots where taken. This is used for backups and allows easy retrieval of deleted or overwritten files. This is done by the regular users and from every time a snapshot was taken - this is just like undelete, only better...

This is very useful. With the cost of backups being as high as it is and with restorations from tape being admin level work (and slow at that) - I know from experience that this ability is extremely useful. I have also asked myself why this isn't implemented in any of the file systems available for Linux (in fact, I only know of its existence in Network-Appliances file servers)."