Index: lams_build/conf/whiteboard/scripts/s_whiteboard.js
===================================================================
diff -u -rcf53a39fbd08dd3125cceba14221ac809ae6df13 -r612dedddab7ffe856fc5cb1626a0f1db55b9cf1d
--- lams_build/conf/whiteboard/scripts/s_whiteboard.js	(.../s_whiteboard.js)	(revision cf53a39fbd08dd3125cceba14221ac809ae6df13)
+++ lams_build/conf/whiteboard/scripts/s_whiteboard.js	(.../s_whiteboard.js)	(revision 612dedddab7ffe856fc5cb1626a0f1db55b9cf1d)
@@ -4,18 +4,14 @@
 
 var savedBoards = {};
 var savedUndos = {};
-var saveDelay = false;
+var saveDelay = {};
 
-if (config.backend.enableFileDatabase) {
-    //read saved boards from file
-    fs.readFile("savedBoards.json", (err, data) => {
-        if (err) {
-            return console.log(
-                "No persistend Whiteboard Datafile found... this is not a problem on the first start!"
-            );
-        }
-        savedBoards = JSON.parse(data);
-    });
+if (config.backend.enableFileDatabase){
+	// make sure that folder with saved boards exists
+	fs.mkdirSync("savedBoards", {
+		// this option also mutes an error if path exists
+		recursive : true
+	});
 }
 
 module.exports = {
@@ -27,12 +23,19 @@
             //Clear the whiteboard
             delete savedBoards[wid];
             delete savedUndos[wid];
+			// delete the corresponding file too
+			fs.unlink("savedBoards/" + wid + ".json", function(err) {
+				if (err) {
+					return console.log(err);
+				}
+			});
         } else if (tool === "undo") {
             //Undo an action
             if (!savedUndos[wid]) {
                 savedUndos[wid] = [];
             }
-            if (savedBoards[wid]) {
+			let savedBoard = this.loadStoredData(wid);
+            if (savedBoard) {
                 for (var i = savedBoards[wid].length - 1; i >= 0; i--) {
                     if (savedBoards[wid][i]["username"] == username) {
                         var drawId = savedBoards[wid][i]["drawId"];
@@ -56,9 +59,7 @@
             if (!savedUndos[wid]) {
                 savedUndos[wid] = [];
             }
-            if (!savedBoards[wid]) {
-                savedBoards[wid] = [];
-            }
+			let savedBoard = this.loadStoredData(wid);
             for (var i = savedUndos[wid].length - 1; i >= 0; i--) {
                 if (savedUndos[wid][i]["username"] == username) {
                     var drawId = savedUndos[wid][i]["drawId"];
@@ -67,7 +68,7 @@
                             savedUndos[wid][i]["drawId"] == drawId &&
                             savedUndos[wid][i]["username"] == username
                         ) {
-                            savedBoards[wid].push(savedUndos[wid][i]);
+                            savedBoard.push(savedUndos[wid][i]);
                             savedUndos[wid].splice(i, 1);
                         }
                     }
@@ -92,58 +93,78 @@
                 "setTextboxFontColor",
             ].includes(tool)
         ) {
+			let savedBoard = this.loadStoredData(wid);
             //Save all this actions
-            savedBoards[wid] = savedBoards[wid] ? savedBoards[wid] : [];
             delete content["wid"]; //Delete id from content so we don't store it twice
             if (tool === "setTextboxText") {
-                for (var i = savedBoards[wid].length - 1; i >= 0; i--) {
+                for (var i = savedBoard.length - 1; i >= 0; i--) {
                     //Remove old textbox tex -> dont store it twice
                     if (
-                        savedBoards[wid][i]["t"] === "setTextboxText" &&
-                        savedBoards[wid][i]["d"][0] === content["d"][0]
+                        savedBoard[i]["t"] === "setTextboxText" &&
+                        savedBoard[i]["d"][0] === content["d"][0]
                     ) {
-                        savedBoards[wid].splice(i, 1);
+                        savedBoard.splice(i, 1);
                     }
                 }
             }
-            savedBoards[wid].push(content);
+            savedBoard.push(content);
         }
-		this.saveToDB();
+		this.saveToDB(wid);
     },
-	saveToDB : function(){
+	saveToDB : function(wid){
         if (config.backend.enableFileDatabase) {
             //Save whiteboard to file
-            if (!saveDelay) {
-                saveDelay = true;
+            if (!saveDelay[wid]) {
+                saveDelay[wid] = true;
                 setTimeout(function () {
-                    saveDelay = false;
-                    fs.writeFile("savedBoards.json", JSON.stringify(savedBoards), (err) => {
-                        if (err) {
-                            return console.log(err);
-                        }
-                    });
+                    saveDelay[wid] = false;
+					if (savedBoards[wid]) {
+	                    fs.writeFile("savedBoards/" + wid + ".json", JSON.stringify(savedBoards[wid]), (err) => {
+	                        if (err) {
+								return console.log(err);
+	                        }
+	                    });
+					}
                 }, 1000 * 10); //Save after 10 sec
             }
         }
 	},
+	// Load saved whiteboard
     loadStoredData: function (wid) {
-        //Load saved whiteboard
-        return savedBoards[wid] ? savedBoards[wid] : [];
+		if (wid in savedBoards) {
+			 return savedBoards[wid];
+		}
+        
+	   savedBoards[wid] = [];
+
+	   // try to load from DB
+       if (config.backend.enableFileDatabase) {
+		    //read saved board from file
+			var filePath = "savedBoards/" + wid + ".json";
+			if (fs.existsSync(filePath)) {
+			    var data = fs.readFileSync(filePath);
+				if (data) {
+			    	savedBoards[wid] = JSON.parse(data);
+				}
+			}
+		}
+		
+		return savedBoards[wid];
     },
 	copyStoredData : function(sourceWid, targetWid) {
 		const sourceData = this.loadStoredData(sourceWid);
 		if (sourceData.length === 0 || this.loadStoredData(targetWid).lenght > 0) {
 			return;
 		}
 		savedBoards[targetWid] = sourceData.slice();
-		this.saveToDB();
+		this.saveToDB(targetWid);
 	},
 	saveData: function(wid, data) {
 		const existingData = this.loadStoredData(wid);
-		if (existingData.lenght > 0 || !data) {
+		if (existingData.length > 0 || !data) {
 			return;
 		}
 		savedBoards[wid] = JSON.parse(data);
-		this.saveToDB();
+		this.saveToDB(wid);
 	}
 };