diff --git a/tests/common.sh b/tests/common.sh
new file mode 100644
index 00000000..32a259be
--- /dev/null
+++ b/tests/common.sh
@@ -0,0 +1,35 @@
+#!/bin/bash -ex
+
+if [ ! "$BASH_VERSION" ] ; then
+    echo "Use bash to run this script ($0)" 1>&2
+    exit 1
+fi
+
+format_error()
+{
+    echo $(echo -n -e "\033[1;31m")$1$(echo -n -e "\033[m")
+    $ETCDCTL get --prefix /vitastor > ./testdata/etcd-dump.txt
+    exit 1
+}
+format_green()
+{
+    echo $(echo -n -e "\033[1;32m")$1$(echo -n -e "\033[m")
+}
+
+cd `dirname $0`/..
+
+trap 'kill -9 $(jobs -p)' EXIT
+
+ETCD=${ETCD:-etcd}
+ETCD_PORT=${ETCD_PORT:-12379}
+
+rm -rf ./testdata
+mkdir -p ./testdata
+
+$ETCD -name etcd_test --data-dir ./testdata/etcd \
+    --advertise-client-urls http://127.0.0.1:$ETCD_PORT --listen-client-urls http://127.0.0.1:$ETCD_PORT \
+    --initial-advertise-peer-urls http://127.0.0.1:$((ETCD_PORT+1)) --listen-peer-urls http://127.0.0.1:$((ETCD_PORT+1)) \
+    --max-txn-ops=100000 --auto-compaction-retention=10 --auto-compaction-mode=revision &>./testdata/etcd.log &
+ETCD_PID=$!
+ETCD_URL=127.0.0.1:$ETCD_PORT/v3
+ETCDCTL="${ETCD}ctl --endpoints=http://$ETCD_URL"
diff --git a/tests/test_failure_domain.sh b/tests/test_failure_domain.sh
new file mode 100755
index 00000000..bc245d79
--- /dev/null
+++ b/tests/test_failure_domain.sh
@@ -0,0 +1,29 @@
+#!/bin/bash -ex
+
+. `dirname $0`/common.sh
+
+TIME=$(date '+%s')
+$ETCDCTL put /vitastor/config/global '{"placement_levels":{"rack":1,"host":2,"osd":3}}'
+$ETCDCTL put /vitastor/config/node_placement '{"rack1":{"level":"rack"},"rack2":{"level":"rack"},"host1":{"level":"host","parent":"rack1"},"host2":{"level":"host","parent":"rack1"},"host3":{"level":"host","parent":"rack2"},"host4":{"level":"host","parent":"rack2"}}'
+$ETCDCTL put /vitastor/osd/stats/1 '{"host":"host1","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/osd/stats/2 '{"host":"host1","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/osd/stats/3 '{"host":"host2","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/osd/stats/4 '{"host":"host2","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/osd/stats/5 '{"host":"host3","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/osd/stats/6 '{"host":"host3","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/osd/stats/7 '{"host":"host4","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/osd/stats/8 '{"host":"host4","size":1073741824,"time":"'$TIME'"}'
+$ETCDCTL put /vitastor/config/pools '{"1":{"name":"testpool","scheme":"replicated","pg_size":2,"pg_minsize":1,"pg_count":4,"failure_domain":"rack"}}'
+
+cd mon
+npm install
+cd ..
+node mon/mon-main.js --etcd_url http://$ETCD_URL --etcd_prefix "/vitastor" &>./testdata/mon.log &
+MON_PID=$!
+
+sleep 2
+
+etcdctl --endpoints=http://localhost:12379 get --prefix /vitastor/config/pgs --print-value-only | \
+    jq -s -e '([ .[0].items["1"] | .[].osd_set | map_values(. | tonumber) | select((.[0] <= 4) != (.[1] <= 4)) ] | length) == 4'
+
+format_green OK
diff --git a/run_tests.sh b/tests/test_write.sh
similarity index 71%
rename from run_tests.sh
rename to tests/test_write.sh
index 4c580c52..c04fb976 100755
--- a/run_tests.sh
+++ b/tests/test_write.sh
@@ -1,42 +1,11 @@
-#!/bin/bash
+#!/bin/bash -ex
 
-if [ ! "$BASH_VERSION" ] ; then
-    echo "Use bash to run this script ($0)" 1>&2
-    exit 1
-fi
+. `dirname $0`/common.sh
 
-format_error()
-{
-    echo $(echo -n -e "\033[1;31m")$1$(echo -n -e "\033[m")
-    $ETCDCTL get --prefix /vitastor > ./testdata/etcd-dump.txt
-    exit 1
-}
-format_green()
-{
-    echo $(echo -n -e "\033[1;32m")$1$(echo -n -e "\033[m")
-}
-
-set -e -x
-
-trap 'kill -9 $(jobs -p)' EXIT
-
-ETCD=${ETCD:-etcd}
-ETCD_PORT=${ETCD_PORT:-12379}
-
-rm -rf ./testdata
-mkdir -p ./testdata
 dd if=/dev/zero of=./testdata/test_osd1.bin bs=1024 count=1 seek=$((1024*1024-1))
 dd if=/dev/zero of=./testdata/test_osd2.bin bs=1024 count=1 seek=$((1024*1024-1))
 dd if=/dev/zero of=./testdata/test_osd3.bin bs=1024 count=1 seek=$((1024*1024-1))
 
-$ETCD -name etcd_test --data-dir ./testdata/etcd \
-    --advertise-client-urls http://127.0.0.1:$ETCD_PORT --listen-client-urls http://127.0.0.1:$ETCD_PORT \
-    --initial-advertise-peer-urls http://127.0.0.1:$((ETCD_PORT+1)) --listen-peer-urls http://127.0.0.1:$((ETCD_PORT+1)) \
-    --max-txn-ops=100000 --auto-compaction-retention=10 --auto-compaction-mode=revision &>./testdata/etcd.log &
-ETCD_PID=$!
-ETCD_URL=127.0.0.1:$ETCD_PORT/v3
-ETCDCTL="${ETCD}ctl --endpoints=http://$ETCD_URL"
-
 ./osd --osd_num 1 --bind_address 127.0.0.1 --etcd_address $ETCD_URL $(node mon/simple-offsets.js --format options --device ./testdata/test_osd1.bin 2>/dev/null) &>./testdata/osd1.log &
 OSD1_PID=$!
 ./osd --osd_num 2 --bind_address 127.0.0.1 --etcd_address $ETCD_URL $(node mon/simple-offsets.js --format options --device ./testdata/test_osd2.bin 2>/dev/null) &>./testdata/osd2.log &