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ceph/doc/dev/rbd-diff.rst

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rbd: implement 'export-diff' and 'import-diff' commands Export a diff of an image from a previous snapshot to a file (or stdout). Import a diff and apply it to an image, and then create the ending snapshot. Signed-off-by: Sage Weil <sage@inktank.com>
2013-03-26 20:32:28 +00:00
RBD Incremental Backup
======================
This is a simple streaming file format for representing a diff between
two snapshots (or a snapshot and the head) of an RBD image.
Header
------
doc/dev/rbd-diff: update incremental file format Signed-off-by: Sage Weil <sage@inktank.com>
2013-03-28 21:19:59 +00:00
"rbd diff v1\n"
rbd: implement 'export-diff' and 'import-diff' commands Export a diff of an image from a previous snapshot to a file (or stdout). Import a diff and apply it to an image, and then create the ending snapshot. Signed-off-by: Sage Weil <sage@inktank.com>
2013-03-26 20:32:28 +00:00
Record
------
Every record has a one byte "tag" that identifies the record type, followed by some other
data.
From snap
---------
u8: 'f'
le32: snap name length
snap name
To snap
-------
u8: 't'
le32: snap name length
snap name
Size
----
u8: 's'
u64: (ending) image size
Updated data
------------
u8: 'w'
le64: offset
le64: length
length bytes of actual data
Zero data
---------
u8: 'z'
le64: offset
le64: length
doc/dev/rbd-diff: update incremental file format Signed-off-by: Sage Weil <sage@inktank.com>
2013-03-28 21:19:59 +00:00
End
---
u8: 'e'
rbd: implement 'export-diff' and 'import-diff' commands Export a diff of an image from a previous snapshot to a file (or stdout). Import a diff and apply it to an image, and then create the ending snapshot. Signed-off-by: Sage Weil <sage@inktank.com>
2013-03-26 20:32:28 +00:00