.I mdadm
will create and devices that are needed.
+.TP
+.B MDADM_NO_SYSTEMCTL
+If
+.I mdadm
+detects that
+.I systemd
+is in use it will normally request
+.I systemd
+to start various background tasks (particularly
+.IR mdmon )
+rather than forking and running them in the background. This can be
+suppressed by setting
+.BR MDADM_NO_SYSTEMCTL=1 .
+
.TP
.B IMSM_NO_PLATFORM
A key value of IMSM metadata is that it allows interoperability with
recovery. You should be aware that interoperability may be
compromised by setting this value.
+.TP
+.B MDADM_GROW_ALLOW_OLD
+If an array is stopped while it is performing a reshape and that
+reshape was making use of a backup file, then when the array is
+re-assembled
+.I mdadm
+will sometimes complain that the backup file is too old. If this
+happens and you are certain it is the right backup file, you can
+over-ride this check by setting
+.B MDADM_GROW_ALLOW_OLD=1
+in the environment.
+
.TP
.B MDADM_CONF_AUTO
Any string given in this variable is added to the start of the