doc: explain the consequence of enabling mirroring through monitor commands

Signed-off-by: Jos Collin <jcollin@redhat.com>

diff --git a/doc/cephfs/cephfs-mirroring.rst b/doc/cephfs/cephfs-mirroring.rst
index 1a1575482811d467aa51413f20bfdc86723e87fc..8bdfefa12686394eb34dac4ab5c8ca91b0f11e85 100644 (file)
--- a/doc/cephfs/cephfs-mirroring.rst
+++ b/doc/cephfs/cephfs-mirroring.rst
@@ -120,7 +120,9 @@ system, run a command of the following form:
 
 .. note:: "Mirroring module" commands are prefixed with ``fs snapshot mirror``.
    This distinguishes them from "monitor commands", which are prefixed with ``fs
-   mirror``. Be sure (in this context) to use module commands.
+   mirror``. Enabling mirroring by using monitor commands will result in the mirror daemon
+   entering the "failed" state due to the absence of the `cephfs_mirror` index object.
+   So be sure (in this context) to use module commands.
 
 To disable mirroring for a given file system, run a command of the following form: