doc/man: define --num-rep, --min-rep and --max-rep

Explain the "--num-rep", "--min-rep", and "--max-rep" options, which are
required when running "crushtool" commands with the "--show-mappings"
flag. Originally reported by Brad Fitzpatrick.

https://tracker.ceph.com/issues/58374

Signed-off-by: Zac Dover <zac.dover@gmail.com>

diff --git a/doc/man/8/crushtool.rst b/doc/man/8/crushtool.rst
index 80c25ca2653fb70225e642bc90cc701abe636977..4c848659655d0cee9bc80789b42ca749fa29c0c2 100644 (file)
--- a/doc/man/8/crushtool.rst
+++ b/doc/man/8/crushtool.rst
@@ -108,6 +108,16 @@ pools; it only runs simulations by mapping values in the range
    shows that value **24** is mapped to devices **[11,6]** by rule
    **1**.
 
+   One of the following is required when using the ``--show-mappings`` option:
+   
+        (a) ``--num-rep`` 
+        (b) both ``--min-rep`` and ``--max-rep``
+
+   ``--num-rep`` stands for "number of replicas, indicates the number of
+   replicas in a pool, and is used to specify an exact number of replicas (for
+   example ``--num-rep 5``). ``--min-rep`` and ``--max-rep`` are used together
+   to specify a range of replicas (for example, ``--min-rep 1 --max-rep 10``).
+
 .. option:: --show-bad-mappings
 
    Displays which value failed to be mapped to the required number of