diff --git a/tests/README.md b/tests/README.md
index b61c6977..68f3b157 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -25,8 +25,9 @@ All options can be seen by running with -h.
 This script is built to test multi-node systems on one host by using
 different mounts of the same devices.  The script creates a fake block
 device in front of each fs block device for each mount that will be
-tested.  Currently it will create free loop devices and will mount on
-/mnt/test.[0-9].
+tested.  It will create predictable device mapper devices and mounts
+them on /mnt/test.N.  These static device names and mount paths limit
+the script to a single execution per host.
 
 All tests will be run by default.  Particular tests can be included or
 excluded by providing test name regular expressions with the -I and -E
@@ -104,8 +105,8 @@ used during the test.
 
 | Variable         | Description          | Origin          | Example           |
 | ---------------- | -------------------  | --------------- | ----------------- |
-| T\_MB[0-9]       | per-mount meta bdev  | created per run | /dev/loop0        |
-| T\_DB[0-9]       | per-mount data bdev  | created per run | /dev/loop1        |
+| T\_MB[0-9]       | per-mount meta bdev  | created per run | /dev/mapper/\_scoutfs\_test\_meta\_[0-9]        |
+| T\_DB[0-9]       | per-mount data bdev  | created per run | /dev/mapper/\_scoutfs\_test\_data\_[0-9]        |
 | T\_D[0-9]        | per-mount test dir   | made for test   | /mnt/test.[0-9]/t |
 | T\_META\_DEVICE  | main FS meta bdev    | -M              | /dev/vda          |
 | T\_DATA\_DEVICE  | main FS data bdev    | -D              | /dev/vdb          |
diff --git a/tests/run-tests.sh b/tests/run-tests.sh
index 1202cada..2890f58a 100755
--- a/tests/run-tests.sh
+++ b/tests/run-tests.sh
@@ -326,16 +326,10 @@ unmount_all() {
 		cmd wait $p
 	done
 
-	# delete all temp meta devices
-	for dev in $(losetup --associated "$T_META_DEVICE" | cut -d : -f 1); do
-		if [ -e "$dev" ]; then
-			cmd losetup -d "$dev"
-		fi
-	done
-	# delete all temp data devices
-	for dev in $(losetup --associated "$T_DATA_DEVICE" | cut -d : -f 1); do
-		if [ -e "$dev" ]; then
-			cmd losetup -d "$dev"
+	# delete all temp devices
+	for dev in /dev/mapper/_scoutfs_test_*; do
+		if [ -b "$dev" ]; then
+			cmd dmsetup remove $dev
 		fi
 	done
 }
@@ -434,6 +428,12 @@ $T_UTILS/fenced/scoutfs-fenced > "$T_FENCED_LOG" 2>&1 &
 fenced_pid=$!
 fenced_log "started fenced pid $fenced_pid in the background"
 
+# setup dm tables
+echo "0 $(blockdev --getsz $T_META_DEVICE) linear $T_META_DEVICE 0" > \
+	$T_RESULTS/dmtable.meta
+echo "0 $(blockdev --getsz $T_DATA_DEVICE) linear $T_DATA_DEVICE 0" > \
+	$T_RESULTS/dmtable.data
+
 #
 # mount concurrently so that a quorum is present to elect the leader and
 # start a server.
@@ -442,10 +442,13 @@ msg "mounting $T_NR_MOUNTS mounts on meta $T_META_DEVICE data $T_DATA_DEVICE"
 pids=""
 for i in $(seq 0 $((T_NR_MOUNTS - 1))); do
 
-	meta_dev=$(losetup --find --show $T_META_DEVICE)
-	test -b "$meta_dev" || die "failed to create temp device $meta_dev"
-	data_dev=$(losetup --find --show $T_DATA_DEVICE)
-	test -b "$data_dev" || die "failed to create temp device $data_dev"
+	name="_scoutfs_test_meta_$i"
+	cmd dmsetup create "$name" --table "$(cat $T_RESULTS/dmtable.meta)"
+	meta_dev="/dev/mapper/$name"
+
+	name="_scoutfs_test_data_$i"
+	cmd dmsetup create "$name" --table "$(cat $T_RESULTS/dmtable.data)"
+	data_dev="/dev/mapper/$name"
 
 	dir="/mnt/test.$i"
 	test -d "$dir" || cmd mkdir -p "$dir"