mds: add comment explaining MDSMap::max_mds

Signed-off-by: Colin McCabe <colin.mccabe@dreamhost.com>

diff --git a/src/mds/MDSMap.h b/src/mds/MDSMap.h
index 7966b4f42dac28bfc5e7f5fef31a98baf6d942ae..69401cde216359ac4c540397cf971317a8987ed7 100644 (file)
--- a/src/mds/MDSMap.h
+++ b/src/mds/MDSMap.h
@@ -171,7 +171,8 @@ protected:
    *    @up + @failed = @in.  @in * @stopped = {}.
    */
 
-  uint32_t max_mds;
+  uint32_t max_mds; /* The maximum number of active MDSes. Also, the maximum rank. */
+
   set<int32_t> in;              // currently defined cluster
   map<int32_t,int32_t> inc;     // most recent incarnation.
   set<int32_t> failed, stopped; // which roles are failed or stopped