diff --git a/check_mdstat.sh b/check_mdstat.sh
index 597661a..467d661 100755
--- a/check_mdstat.sh
+++ b/check_mdstat.sh
@@ -46,6 +46,7 @@ function logLine {
 		echo "  : $@"
 	fi
 }
+NL=$'\n'
 
 CURRENT_RAID=	# string
 function setCurrentRaid {
@@ -64,7 +65,8 @@ function setCurrentRaid {
 
 STATE=		# "active", "started", "inactive"
 LEVEL=		# int
-DEVICES=	# strings separated by whitespace
+declare -A DEVICES	# dict of strings. key = index, value = dev name
+declare -A FAILED_DEVICES
 function setStateAndDevicesAndLevel {
 	# This functions is called for the line that starts a new RAID device by setCurrentRaid, with the complete line in $1
 	# It parses the STATE, the LEVEL and the DEVICES
@@ -78,19 +80,26 @@ function setStateAndDevicesAndLevel {
 	LEVEL="${LEVEL:4}"					# Remove the raid prefix
 
 	for dev1 in $x3; do
-		local dev2="${dev1%[*}"
-		if [ -n "$DEVICES" ]; then DEVICES="$DEVICES "; fi
-		DEVICES="${DEVICES}$dev2"
+		local devName="${dev1%[*}"		# device name
+		local dev2="${dev1#*[}"			# all after device name
+		local devIndex="${dev2%]*}"		# device index
+		local dev3="${dev2#*]}"			# all after device index
+		local devFailed=false
+		DEVICES[$devIndex]="$devName"
+		FAILED_DEVICES[$devIndex]=false
+		if [ -n "$dev3" ]; then
+			FAILED_DEVICES[$devIndex]=true
+		fi
 	done
 
 	log "STATE = $STATE"
 	log "LEVEL = $LEVEL"
-	log "DEVICES = $DEVICES"
+	log "DEVICES = ${DEVICES[@]}"
 }
 
-SIZE_IN_BLOCKS="!"	# int
-NUM_DEVICES=0		# int with number of devices in raid
-BAD_DEVICES=0		# int with number of "_" in "[UUU_UU]"
+SIZE_IN_BLOCKS="!"			# int
+NUM_DEVICES=0				# int with total number of devices in raid
+NUM_ACTIVE_DEVICES=0		# int with number of active devices in raid
 function parseConfigStatusLine {
 	# This function is called for 1st line after the raid definition line
 	# It parses the SIZE_IN_BLOCKS
@@ -98,16 +107,17 @@ function parseConfigStatusLine {
 	line=$(echo $line)	# trim left
 	SIZE_IN_BLOCKS=${line%% *}
 
-	local lastWord=${line##* }	# Get the last word
-	lastWord=${lastWord:1:-1}	# Remove first and last char
-	NUM_DEVICES=${#lastWord}	# str length = num devices
-	lastWord=${lastWord//U/}	# Remove all U, so only _ remain
-	BAD_DEVICES=${#lastWord}	# str length = num bad devices
+	local x1=${line##* }		# Get the last word [UU_]
+	local x2=${line% *}			# Remove the last word
+	local x3=${x2##* }			# Get the last word [3/2]
+	x3=${x3:1:-1}
+	NUM_DEVICES=${x3%/*}
+	NUM_ACTIVE_DEVICES=${x3#*/}
 
 
 	log "SIZE_IN_BLOCKS = $SIZE_IN_BLOCKS"
 	log "NUM_DEVICES = $NUM_DEVICES"
-	log "BAD_DEVICES = $BAD_DEVICES"
+	log "NUM_ACTIVE_DEVICES = $NUM_ACTIVE_DEVICES"
 	# TODO
 }
 
@@ -150,6 +160,14 @@ function printOutputAndExit {
 
 	local result="OK"
 	local info=""
+	local numFailedDevices=0
+	local numSpareDevices=0
+
+	if [ $NUM_ACTIVE_DEVICES -lt $NUM_DEVICES ]; then
+		result="CRITICAL"
+		if [ -n "$info" ]; then info="$info. "; fi
+		info="${info}Missing $(($NUM_DEVICES - $NUM_ACTIVE_DEVICES)) of $NUM_DEVICES devices"
+	fi
 
 	if [ -n "$RECOVERY_PROGRESS" ]; then
 		result="WARNING"
@@ -157,18 +175,26 @@ function printOutputAndExit {
 		info="${info}Recovering: progress=$RECOVERY_PROGRESS% $RECOVERY_INFO"
 	fi
 
+	local devIndices="$(printf "%s\n" "${!DEVICES[@]}" | sort -n)"
+	for devIndex in $devIndices; do
+		if [ -z "${DEVICES[$devIndex]}" ]; then
+			((numSpareDevies++))
+			continue
+		fi
+		if ${FAILED_DEVICES[$devIndex]}; then
+			result="CRITICAL"
+			((numFailedDevices++))
+			if [ -n "$info" ]; then info="$info. "; fi
+			info="${info}Device ${DEVICES[$devIndex]} failed"
+		fi
+	done
+
 	if [ "$STATE" != "active" -a "$STATE" != "started" ]; then
 		result="CRITICAL"
 		if [ -n "$info" ]; then info="$info. "; fi
 		info="${info}State is $STATE"
 	fi
 
-	if [ $BAD_DEVICES -gt 0 ]; then
-		result="CRITICAL"
-		if [ -n "$info" ]; then info="$info. "; fi
-		info="${info}Missing $BAD_DEVICES of $NUM_DEVICES devices"
-	fi
-
 	echo -n "$result"
 	if [ -n "$info" ]; then
 		echo -n ": $info"
@@ -178,10 +204,23 @@ function printOutputAndExit {
 	echo -n " 'raid level'=$LEVEL"
 	echo -n " 'size in blocks'=$SIZE_IN_BLOCKS"
 	echo -n " 'num devices'=$NUM_DEVICES"
-	echo -n " 'num bad devices'=$BAD_DEVICES;;1;0;$NUM_DEVICES"
+	echo -n " 'num failed devices'=$numFailedDevices;;1;0;$NUM_DEVICES"
+	echo -n " 'num spare devices'=$numSpareDevices;;;0;$NUM_DEVICES"
 	if [ -n "$RECOVERY_PROGRESS" ]; then
 		echo -n " 'recovery progress'=$RECOVERY_PROGRESS%;0;;0;100"
 	fi
+	for devIndex in $devIndices; do
+		if [ -z "${DEVICES[$devIndex]}" ]; then
+			echo -n " 'device $devIndex: spare'=$devIndex"
+			continue
+		fi
+		if ${FAILED_DEVICES[$devIndex]}; then
+			echo -n " 'device $devIndex: ${DEVICES[$devIndex]} failed'=$devIndex;;$devIndex'"
+			continue
+		fi
+		echo -n " 'device $devIndex: ${DEVICES[$devIndex]}'=$devIndex"
+	done
+
 	echo
 
 	case $result in
@@ -205,7 +244,7 @@ while IFS= read -r line; do
 			1) parseConfigStatusLine "$line";;
 			*) parseBitmapOrRecoveryLine "$line";;
 		esac
-		HAD_TARGET_RAID=$(($HAD_TARGET_RAID+1))
+		((HAD_TARGET_RAID++))
 	elif [ $HAD_TARGET_RAID -gt 0 ]; then
 		printOutputAndExit
 	fi
diff --git a/test/1missing.output b/test/1missing.output
index 808f869..282cb3a 100644
--- a/test/1missing.output
+++ b/test/1missing.output
@@ -1 +1 @@
-CRITICAL: Missing 1 of 4 devices | 'raid level'=5 'size in blocks'=1465151808 'num devices'=4 'num bad devices'=1;;1;0;4
+CRITICAL: Missing 1 of 4 devices | 'raid level'=5 'size in blocks'=1465151808 'num devices'=4 'num failed devices'=0;;1;0;4 'num spare devices'=0;;;0;4 'device 0: sda1'=0 'device 1: sdb1'=1 'device 2: sdd1'=2
diff --git a/test/OK1.output b/test/OK1.output
index 4b618cd..8c89504 100644
--- a/test/OK1.output
+++ b/test/OK1.output
@@ -1 +1 @@
-OK | 'raid level'=1 'size in blocks'=976430080 'num devices'=2 'num bad devices'=0;;1;0;2
+OK | 'raid level'=1 'size in blocks'=976430080 'num devices'=2 'num failed devices'=0;;1;0;2 'num spare devices'=0;;;0;2 'device 0: sda1'=0 'device 1: sdb1'=1
diff --git a/test/OK2.output b/test/OK2.output
index ebe7842..f033258 100644
--- a/test/OK2.output
+++ b/test/OK2.output
@@ -1 +1 @@
-OK | 'raid level'=5 'size in blocks'=1250241792 'num devices'=5 'num bad devices'=0;;1;0;5
+OK | 'raid level'=5 'size in blocks'=1250241792 'num devices'=5 'num failed devices'=0;;1;0;5 'num spare devices'=0;;;0;5 'device 0: sde1'=0 'device 1: sdc1'=1 'device 2: sdd1'=2 'device 4: sdf1'=4 'device 5: sdb1'=5
diff --git a/test/OK3.output b/test/OK3.output
index f4b32ff..8607af1 100644
--- a/test/OK3.output
+++ b/test/OK3.output
@@ -1 +1 @@
-OK | 'raid level'=5 'size in blocks'=1318680576 'num devices'=10 'num bad devices'=0;;1;0;10
+OK | 'raid level'=5 'size in blocks'=1318680576 'num devices'=10 'num failed devices'=0;;1;0;10 'num spare devices'=0;;;0;10 'device 0: sdc1'=0 'device 1: sdd1'=1 'device 2: sde1'=2 'device 3: sdf1'=3 'device 4: sdg1'=4 'device 5: sdh1'=5 'device 6: sdi1'=6 'device 7: sdj1'=7 'device 8: sdk1'=8 'device 9: sdl1'=9
diff --git a/test/bitmap.output b/test/bitmap.output
index 3c4e3a2..83c86f1 100644
--- a/test/bitmap.output
+++ b/test/bitmap.output
@@ -1 +1 @@
-OK | 'raid level'=6 'size in blocks'=1225557760 'num devices'=7 'num bad devices'=0;;1;0;7
+OK | 'raid level'=6 'size in blocks'=1225557760 'num devices'=7 'num failed devices'=0;;1;0;7 'num spare devices'=0;;;0;7 'device 0: sdf1'=0 'device 1: sde1'=1 'device 2: sdd1'=2 'device 3: sdc1'=3 'device 4: sdb1'=4 'device 5: sda1'=5 'device 6: hdb1'=6
diff --git a/test/recovery.output b/test/recovery.output
index ac8b429..44c3596 100644
--- a/test/recovery.output
+++ b/test/recovery.output
@@ -1 +1 @@
-WARNING: Recovering: progress=12.6% finish=127.5min speed=33440K/sec | 'raid level'=5 'size in blocks'=1464725760 'num devices'=6 'num bad devices'=0;;1;0;6 'recovery progress'=12.6%;0;;0;100
+WARNING: Missing 1 of 6 devices. Recovering: progress=12.6% finish=127.5min speed=33440K/sec | 'raid level'=5 'size in blocks'=1464725760 'num devices'=6 'num failed devices'=0;;1;0;6 'num spare devices'=0;;;0;6 'recovery progress'=12.6%;0;;0;100 'device 0: sdc1'=0 'device 1: sdd1'=1 'device 2: sde1'=2 'device 3: sdf1'=3 'device 4: sdg1'=4 'device 6: sdh1'=6