doc: clarify availability vs integrity

(cherry picked from commit 3888cf77075eceb079b1d5a8ce19092d12fd82bd)

diff --git a/doc/architecture.rst b/doc/architecture.rst
index 2b28f9af1eac3e77db406d86a448096ec8ce424f..23c614a230e28d59bde81948a847394a3915b0e7 100644 (file)
--- a/doc/architecture.rst
+++ b/doc/architecture.rst
@@ -739,7 +739,8 @@ of ``K+M`` so that each chunk is stored in an OSD in the acting set. The rank of
 the chunk is stored as an attribute of the object.
 
 For instance an erasure coded pool can be created to use five OSDs (``K+M = 5``) and
-sustain the loss of two of them (``M = 2``).
+sustain the loss of two of them (``M = 2``). Data may be unavailable until (``K+1``)
+shards are restored.
 
 Reading and Writing Encoded Chunks
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~