On Thu, Oct 7, 2010 at 6:39 AM, Francis Galiegue <fgaliegue@xxxxxxxxx> wrote: > While I fully understand (and use) the purpose of snapshots, I don't > quite fathom the use case for subvolumes, apart from btrfs-convert... > Why has btrfs grown such a feature in the first place? Can someone > give me a use case for them? I'm new here; I trust that someone will correct me if wrong: As I understand it, since snapshotting works on volumes, having subvolumes allows a smaller thing that you can take a snapshot of. A use case? One could give each user on a multi-user system their own subvolume rather than their own directory, under /home/... and then take snapshots of these home directories to implement regular backups (1)without duplicating unchanged files and (2) with independence between the users. As to why they exist, I understand that they began as an implementation detail of snapshots, rather than their creation having been driven by the needs of a particular use case, and one could legitimately criticize currently offered use cases (such as the one above) as contrived. I believe it is fair to consider a new subvolume as equivalent of a snapshot of an empty file system. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
