On Wed, Sep 4, 2019 at 9:16 AM Swâmi Petaramesh <sw...@petaramesh.org> wrote: > > Hi list, > > Is there an advised way to completely “clone” a complete BTRFS > filesystem, I mean to get an exact copy of a BTRFS filesystem including > subvolumes (even readonly snapshots) and complete file attributes > including extended attributes, ACLs and so, to another storage pool, > possibly defined with a different RAID geometry or compression ? >
As long as you do not use top level subvolume directly (all data is located in subolumes), send/receive should work. > The question boils down to getting an exact backup replica of a given > BTRFS filesystem that could be restored to something logically > absolutely identical. > > The usual backup tools have no clue about share extents, snapshots and > the like, and using btrfs send/receive for individual subvols is a real > pain in a BTRFS filesystem that may contain hundreds of snapshots of > different BTRFS subvols plus deduplication etc. > Shared extents could be challenging. You can provide this information to "btrfs send", but for one, there is no direct visibility into which subvolumes share extents with given subvolume, so no way to build corresponding list for "btrfs send". I do not even know if this information can be obtained without exhaustive search over all extents. Second, btrfs send/receive only allows sharing of full extents which means there is no guarantee of identical structure on receiving side. > So on a practical standpoint, how can one backup and restore a full > BTRFS structure ? > > (I know of tools like partclone that may or may not do the job as they > usually lack behind recent BTRFS features, and may not be able to clone > BTRFS RAID setups for example...) > > TIA. > > ॐ > > -- > Swâmi Petaramesh <sw...@petaramesh.org> PGP 9076E32E
