diff --git a/check_iostat b/check_iostat
index 2aadb49..e4f8978 100644
--- a/check_iostat
+++ b/check_iostat
@@ -90,16 +90,17 @@ if (-d "$disk") {
     close(MOUNTS);
 }
 
+$disk =~ s/^\/dev\/mapper\///;
+$disk =~ s/^\/dev\///;
+
 if (! -b "/dev/$disk") {
     if (-b "/dev/mapper/$disk") {
         my @f = stat("/dev/mapper/$disk");
-	$f[6] %= 256;
-	$disk = "dm-$f[6]";
-    } elsif (-b $disk) {
-        # take as is
+        $f[6] %= 256;
+        $disk = "dm-$f[6]";
     } else {
-	warn "ERROR: Device incorrectly specified\n";
-	HELP_MESSAGE();
+        warn "ERROR: Device incorrectly specified\n";
+        HELP_MESSAGE();
     }
 }
 
diff --git a/monitoring-plugins-sar-perf.changes b/monitoring-plugins-sar-perf.changes
index e38a303..8b19d71 100644
--- a/monitoring-plugins-sar-perf.changes
+++ b/monitoring-plugins-sar-perf.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Wed Dec 11 18:10:48 CET 2019 - ro@suse.de
+
+- check_iostat: sanitize dev name to properly match iostat output 
+
 -------------------------------------------------------------------
 Thu Dec  5 16:34:19 CET 2019 - ro@suse.de