diff --git a/db/backend_test.go b/db/backend_test.go
index 3d10c66c..9dc17201 100644
--- a/db/backend_test.go
+++ b/db/backend_test.go
@@ -15,30 +15,26 @@ func testBackendGetSetDelete(t *testing.T, backend string) {
 	dir, dirname := cmn.Tempdir(fmt.Sprintf("test_backend_%s_", backend))
 	defer dir.Close()
 	db := NewDB("testdb", backend, dirname)
-	require.Nil(t, db.Get([]byte("")))
+	key := []byte("abc")
+	require.Nil(t, db.Get(key))
 
 	// Set empty ("")
-	db.Set([]byte(""), []byte(""))
-	require.NotNil(t, db.Get([]byte("")))
-	require.Empty(t, db.Get([]byte("")))
+	db.Set(key, []byte(""))
+	require.NotNil(t, db.Get(key))
+	require.Empty(t, db.Get(key))
 
 	// Set empty (nil)
-	db.Set([]byte(""), nil)
-	require.NotNil(t, db.Get([]byte("")))
-	require.Empty(t, db.Get([]byte("")))
+	db.Set(key, nil)
+	require.NotNil(t, db.Get(key))
+	require.Empty(t, db.Get(key))
 
 	// Delete
-	db.Delete([]byte(""))
-	require.Nil(t, db.Get([]byte("")))
+	db.Delete(key)
+	require.Nil(t, db.Get(key))
 }
 
 func TestBackendsGetSetDelete(t *testing.T) {
 	for dbType, _ := range backends {
-		if dbType == "fsdb" {
-			// TODO: handle
-			// fsdb cant deal with length 0 keys
-			continue
-		}
 		testBackendGetSetDelete(t, dbType)
 	}
 }
diff --git a/db/c_level_db.go b/db/c_level_db.go
index 11a6e5ff..47e79dfa 100644
--- a/db/c_level_db.go
+++ b/db/c_level_db.go
@@ -48,6 +48,7 @@ func NewCLevelDB(name string, dir string) (*CLevelDB, error) {
 }
 
 func (db *CLevelDB) Get(key []byte) []byte {
+	panicNilKey(key)
 	res, err := db.db.Get(db.ro, key)
 	if err != nil {
 		panic(err)
@@ -56,10 +57,12 @@ func (db *CLevelDB) Get(key []byte) []byte {
 }
 
 func (db *CLevelDB) Has(key []byte) bool {
+	panicNilKey(key)
 	panic("not implemented yet")
 }
 
 func (db *CLevelDB) Set(key []byte, value []byte) {
+	panicNilKey(key)
 	err := db.db.Put(db.wo, key, value)
 	if err != nil {
 		panic(err)
@@ -67,6 +70,7 @@ func (db *CLevelDB) Set(key []byte, value []byte) {
 }
 
 func (db *CLevelDB) SetSync(key []byte, value []byte) {
+	panicNilKey(key)
 	err := db.db.Put(db.woSync, key, value)
 	if err != nil {
 		panic(err)
@@ -74,6 +78,7 @@ func (db *CLevelDB) SetSync(key []byte, value []byte) {
 }
 
 func (db *CLevelDB) Delete(key []byte) {
+	panicNilKey(key)
 	err := db.db.Delete(db.wo, key)
 	if err != nil {
 		panic(err)
@@ -81,6 +86,7 @@ func (db *CLevelDB) Delete(key []byte) {
 }
 
 func (db *CLevelDB) DeleteSync(key []byte) {
+	panicNilKey(key)
 	err := db.db.Delete(db.woSync, key)
 	if err != nil {
 		panic(err)
diff --git a/db/fsdb.go b/db/fsdb.go
index 19ea9fa3..116dc3ee 100644
--- a/db/fsdb.go
+++ b/db/fsdb.go
@@ -119,7 +119,8 @@ func (db *FSDB) DeleteSync(key []byte) {
 // NOTE: Implements atomicSetDeleter.
 func (db *FSDB) DeleteNoLock(key []byte) {
 	panicNilKey(key)
-	err := remove(string(key))
+	path := db.nameToPath(key)
+	err := remove(path)
 	if os.IsNotExist(err) {
 		return
 	} else if err != nil {
@@ -210,7 +211,7 @@ func read(path string) ([]byte, error) {
 // Write some bytes from a file.
 // CONTRACT: returns os errors directly without wrapping.
 func write(path string, d []byte) error {
-	f, err := os.OpenFile(path, os.O_CREATE|os.O_EXCL|os.O_WRONLY, keyPerm)
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, keyPerm)
 	if err != nil {
 		return err
 	}