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Diffstat (limited to 'src/ceph/doc/dev/rbd-diff.rst')
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1 files changed, 0 insertions, 146 deletions
diff --git a/src/ceph/doc/dev/rbd-diff.rst b/src/ceph/doc/dev/rbd-diff.rst deleted file mode 100644 index 083c131..0000000 --- a/src/ceph/doc/dev/rbd-diff.rst +++ /dev/null @@ -1,146 +0,0 @@ -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 -~~~~~~ - -"rbd diff v1\\n" - -Metadata records -~~~~~~~~~~~~~~~~ - -Every record has a one byte "tag" that identifies the record type, -followed by some other data. - -Metadata records come in the first part of the image. Order is not -important, as long as all the metadata records come before the data -records. - -From snap ---------- - -- u8: 'f' -- le32: snap name length -- snap name - -To snap -------- - -- u8: 't' -- le32: snap name length -- snap name - -Size ----- - -- u8: 's' -- le64: (ending) image size - -Data Records -~~~~~~~~~~~~ - -These records come in the second part of the sequence. - -Updated data ------------- - -- u8: 'w' -- le64: offset -- le64: length -- length bytes of actual data - -Zero data ---------- - -- u8: 'z' -- le64: offset -- le64: length - - -Final Record -~~~~~~~~~~~~ - -End ---- - -- u8: 'e' - - -Header -~~~~~~ - -"rbd diff v2\\n" - -Metadata records -~~~~~~~~~~~~~~~~ - -Every record has a one byte "tag" that identifies the record type, -followed by length of data, and then some other data. - -Metadata records come in the first part of the image. Order is not -important, as long as all the metadata records come before the data -records. - -In v2, we have the following metadata in each section: -(1 Bytes) tag. -(8 Bytes) length. -(n Bytes) data. - -In this way, we can skip the unrecognized tag. - -From snap ---------- - -- u8: 'f' -- le64: length of appending data (4 + length) -- le32: snap name length -- snap name - -To snap -------- - -- u8: 't' -- le64: length of appending data (4 + length) -- le32: snap name length -- snap name - -Size ----- - -- u8: 's' -- le64: length of appending data (8) -- le64: (ending) image size - -Data Records -~~~~~~~~~~~~ - -These records come in the second part of the sequence. - -Updated data ------------- - -- u8: 'w' -- le64: length of appending data (8 + 8 + length) -- le64: offset -- le64: length -- length bytes of actual data - -Zero data ---------- - -- u8: 'z' -- le64: length of appending data (8 + 8) -- le64: offset -- le64: length - - -Final Record -~~~~~~~~~~~~ - -End ---- - -- u8: 'e' |