parse iostat for disk busy average

check_disk_busy

@@ -6,20 +6,31 @@
 # Date: 11/16/12
 # License: MIT
 
-sample_time=1 # seconds to sample
-
-# Extract the values from kstat
-getvals() {
-	kstat -p ::"$disk":{rtime,wtime,snaptime}
-}
-
-# populate the kstat keys into variables
-populate() {
-	local i=$1
-	while read name val; do
-		IFS=: read _ _ _ key <<< "$name"
-		read "$key$i" <<< "$val"
-	done < <(getvals)
+function busy() {
+	iostat -xr 1 2 |\
+	awk -F, '
+	BEGIN {
+		max = -1;
+	}
+	/^sd[0-9]/ {
+		d = $1;
+		sub(/^sd/,"",d);
+		if (d > max) {
+			max = d;
+			next;
+		}
+		if ($2||$3||$4||$5||$6||$7||$8||$9) {
+			i++;
+			busy+=$10;
+		}
+	}
+	END {
+		if (i) {
+			printf("%d\n", (busy / i) + .5);
+		} else {
+			print "0"
+		}
+	}'
 }
 
 warning=90
@@ -34,21 +45,11 @@ while getopts 'nw:c:' option; do
 done
 shift $((OPTIND - 1))
 
-disk=${1:-sd1}
-
-# grab the values, sleep for $sample_time seconds, grab more values
-populate 1
-sleep "$sample_time"
-populate 2
-
-# calculate the percentage of time spent doing work during $sample_time seconds
-busy=$(bc <<< "((100 * $rtime2 + $wtime2) - (100 * $rtime1 + $wtime1)) / ($snaptime2 - $snaptime1)")
+busy=$(busy)
 
 # alert
 if [[ -z "$busy" ]]; then
 	echo 'unknown: error retrieving data'
-	echo '- possible disks -' >&2
-	kstat -lc disk :::class | awk -F: '{print $3}' >&2
 	exit 3
 elif (( busy >= critical )); then
 	echo -n 'critical: '