remove ceph code

[stor4nfv.git] / src / ceph / doc / dev / bluestore.rst

diff --git a/src/ceph/doc/dev/bluestore.rst b/src/ceph/doc/dev/bluestore.rst
deleted file mode 100644 (file)
index 91d71d0..0000000
--- a/src/ceph/doc/dev/bluestore.rst
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@@ -1,85 +0,0 @@
-===================
-BlueStore Internals
-===================
-
-
-Small write strategies
-----------------------
-
-* *U*: Uncompressed write of a complete, new blob.
-
-  - write to new blob
-  - kv commit
-
-* *P*: Uncompressed partial write to unused region of an existing
-  blob.
-
-  - write to unused chunk(s) of existing blob
-  - kv commit
-
-* *W*: WAL overwrite: commit intent to overwrite, then overwrite
-  async.  Must be chunk_size = MAX(block_size, csum_block_size)
-  aligned.
-
-  - kv commit
-  - wal overwrite (chunk-aligned) of existing blob
-
-* *N*: Uncompressed partial write to a new blob.  Initially sparsely
-  utilized.  Future writes will either be *P* or *W*.
-
-  - write into a new (sparse) blob
-  - kv commit
-
-* *R+W*: Read partial chunk, then to WAL overwrite.
-
-  - read (out to chunk boundaries)
-  - kv commit
-  - wal overwrite (chunk-aligned) of existing blob
-
-* *C*: Compress data, write to new blob.
-
-  - compress and write to new blob
-  - kv commit
-
-Possible future modes
----------------------
-
-* *F*: Fragment lextent space by writing small piece of data into a
-  piecemeal blob (that collects random, noncontiguous bits of data we
-  need to write).
-
-  - write to a piecemeal blob (min_alloc_size or larger, but we use just one block of it)
-  - kv commit
-
-* *X*: WAL read/modify/write on a single block (like legacy
-  bluestore).  No checksum.
-
-  - kv commit
-  - wal read/modify/write
-
-Mapping
--------
-
-This very roughly maps the type of write onto what we do when we
-encounter a given blob.  In practice it's a bit more complicated since there
-might be several blobs to consider (e.g., we might be able to *W* into one or
-*P* into another), but it should communicate a rough idea of strategy.
-
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-|                          | raw    | raw (cached) | csum (4 KB) | csum (16 KB) | comp (128 KB) |
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-| 128+ KB (over)write      | U      | U            | U           | U            | C             |
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-| 64 KB (over)write        | U      | U            | U           | U            | U or C        |
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-| 4 KB overwrite           | W      | P | W        | P | W       | P | R+W      | P | N (F?)    |
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-| 100 byte overwrite       | R+W    | P | W        | P | R+W     | P | R+W      | P | N (F?)    |
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-| 100 byte append          | R+W    | P | W        | P | R+W     | P | R+W      | P | N (F?)    |
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-| 4 KB clone overwrite     | P | N  | P | N        | P | N       | P | N        | N (F?)        |
-+--------------------------+--------+--------------+-------------+--------------+---------------+
-| 100 byte clone overwrite | P | N  | P | N        | P | N       | P | N        | N (F?)        |
-+--------------------------+--------+--------------+-------------+--------------+---------------+