doc: clarify availability vs integrity

(cherry picked from commit 3888cf77075eceb079b1d5a8ce19092d12fd82bd)

diff --git a/doc/architecture.rst b/doc/architecture.rst
index 22993af5eec4ad2ab3464a426bd8a50d26c4ae7c..d8e1b03ac3ea1f1baafd1e466b72a0c0b72197f5 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
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~