mdadm/SOURCES/md-auto-readd.rule

#
# Enable/Disable - default is Disabled
# to disable this rule, GOTO="md_end" should be the first active command.
# to enable this rule, Comment out GOTO="md_end". 
GOTO="md_end"

# Required: MD arrays must have a bitmap for transient devices to
# be added back in the array.
# mdadm -CR /dev/md0 -l1 -n2 /dev/sd[ab] –bitmap=internal

# Don't process any events if anaconda is running as anaconda brings up
# raid devices manually
ENV{ANACONDA}=="?*", GOTO="md_end"

# Also don't process disks that are slated to be a multipath device
ENV{DM_MULTIPATH_DEVICE_PATH}=="1", GOTO="md_end"

# We process add events on block devices (since they are ready as soon as
# they are added to the system)

ACTION!="add", GOTO="md_end"
ENV{ID_FS_TYPE}!="linux_raid_member", GOTO="md_end"
SUBSYSTEM=="block", RUN{program}+="/usr/sbin/md-auto-readd.sh $devnode"

#
# Land here to exit cleanly
LABEL="md_end"