New flag --no-degraded

Use to avoid starting arrays if there are
fewer devices available than last time the array was started.
This is only needed with --scan, as with --scan, that behaviour
is the default.

Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 13 insertions, 2 deletions

diff --git a/mdadm.8 b/mdadm.8
index 82f9bad..9c113f0 100644
--- a/mdadm.8
+++ b/mdadm.8
@@ -603,8 +603,9 @@ Assemble the array even if some superblocks appear out-of-date
 
 .TP
 .BR -R ", " --run
-Attempt to start the array even if fewer drives were given than are
-needed for a full array. Normally if not all drives are found and
+Attempt to start the array even if fewer drives were given than were
+present last time the array was active.  Normally if not all the
+expected drives are found and
 .B --scan
 is not used, then the array will be assembled but not started.
 With
@@ -612,6 +613,16 @@ With
 an attempt will be made to start it anyway.
 
 .TP
+.B --no-degraded
+This is the reverse of
+.B --run
+in that it inhibits the started if array unless all expected drives
+are present.  This is only needed with
+.B --scan
+and can be used if you physical connections to devices are
+not as reliable as you would like.
+
+.TP
 .BR -a ", " "--auto{=no,yes,md,mdp,part}"
 See this option under Create and Build options.