Is there any tools that allows this use case:
- I have a LVM2 partition
- I periodically create snapshots of it, save them (
create_new_snapshot --directory=/media/external_storage/snapshots/ --input=/dev/mapper/vg-vol_snapshot --name=qwerty), and remove. Only changed blocks are expected to be saved by the tool. The tool is not expected to be LVM-specific, just accept a single big file which is expected to share many blocks with previous such big file. Good thing if compression (with random access preserved) supported...
I can mount (using FUSE or NBD or some other thing) any saved snapshot without fully unpacking it anywhere.
touch /root/mountpoint view_external_snapshot --mountpoint=/root/mountpoint --directory=/media/external_storage/snapshots/ --name=qwerty mount -o loop -t reiserfs /root/mountpoint /root/tmpmnt
The closest thing is
rdiff-backup), but I'm not sure if I can access the content of base+delta without unpacking (
rdiff patch) it first...
Other related thing is cloop. It accepts big file as input, compresses it and allows to access as block device after. But there I can't store deltas, only full snapshot...
Note: the question is not about filesystem-level backup (like in duplicity, rdiff-backup, rsnapshot).