diff --git a/apps/admin_export/settings.php b/apps/admin_export/settings.php
index 8308a2b89b..1685e5c0ca 100644
--- a/apps/admin_export/settings.php
+++ b/apps/admin_export/settings.php
@@ -26,14 +26,14 @@ if (isset($_POST['admin_export'])) {
     $root = OC::$SERVERROOT . "/";
     $zip = new ZipArchive();
     $filename = sys_get_temp_dir() . "/owncloud_export_" . date("y-m-d_H-i-s") . ".zip";
-    error_log("Creating export file at: " . $filename);
+    OC_Log::write('admin_export',"Creating export file at: " . $filename,OC_Log::INFO);
     if ($zip->open($filename, ZIPARCHIVE::CREATE) !== TRUE) {
 	exit("Cannot open <$filename>\n");
     }
 
     if (isset($_POST['owncloud_system'])) {
 	// adding owncloud system files
-	error_log("Adding owncloud system files to export");
+	OC_Log::write('admin_export',"Adding owncloud system files to export",OC_Log::INFO);
 	zipAddDir($root, $zip, false);
 	foreach (array(".git", "3rdparty", "apps", "core", "files", "l10n", "lib", "ocs", "search", "settings", "tests") as $dirname) {
 	    zipAddDir($root . $dirname, $zip, true, basename($root) . "/");
@@ -43,7 +43,7 @@ if (isset($_POST['admin_export'])) {
     if (isset($_POST['owncloud_config'])) {
 	// adding owncloud config
 	// todo: add database export
-	error_log("Adding owncloud config to export");
+	OC_Log::write('admin_export',"Adding owncloud config to export",OC_Log::INFO);
 	zipAddDir($root . "config/", $zip, true, basename($root) . "/");
 	$zip->addFile($root . '/data/.htaccess', basename($root) . "/data/owncloud.db");
     }
@@ -53,7 +53,7 @@ if (isset($_POST['admin_export'])) {
 	$zip->addFile($root . '/data/.htaccess', basename($root) . "/data/.htaccess");
 	$zip->addFile($root . '/data/index.html', basename($root) . "/data/index.html");
 	foreach (OC_User::getUsers() as $i) {
-	    error_log("Adding owncloud user files of $i to export");
+		OC_Log::write('admin_export',"Adding owncloud user files of $i to export",OC_Log::INFO);
 	    zipAddDir($root . "data/" . $i, $zip, true, basename($root) . "/data/");
 	}
     }
@@ -78,19 +78,19 @@ function zipAddDir($dir, $zip, $recursive=true, $internalDir='') {
     $internalDir.=$dirname.='/';
 
     if ($dirhandle = opendir($dir)) {
-	while (false !== ( $file = readdir($dirhandle))) {
+		while (false !== ( $file = readdir($dirhandle))) {
 
-	    if (( $file != '.' ) && ( $file != '..' )) {
+			if (( $file != '.' ) && ( $file != '..' )) {
 
-		if (is_dir($dir . '/' . $file) && $recursive) {
-		    zipAddDir($dir . '/' . $file, $zip, $recursive, $internalDir);
-		} elseif (is_file($dir . '/' . $file)) {
-		    $zip->addFile($dir . '/' . $file, $internalDir . $file);
+			if (is_dir($dir . '/' . $file) && $recursive) {
+				zipAddDir($dir . '/' . $file, $zip, $recursive, $internalDir);
+			} elseif (is_file($dir . '/' . $file)) {
+				$zip->addFile($dir . '/' . $file, $internalDir . $file);
+			}
+			}
 		}
-	    }
-	}
-	closedir($dirhandle);
+		closedir($dirhandle);
     } else {
-	error_log("Was not able to open directory: " . $dir);
+		OC_Log::write('admin_export',"Was not able to open directory: " . $dir,OC_Log::ERROR);
     }
 }
diff --git a/apps/media/ajax/autoupdate.php b/apps/media/ajax/autoupdate.php
index ff0923ca03..a78b5e25dd 100644
--- a/apps/media/ajax/autoupdate.php
+++ b/apps/media/ajax/autoupdate.php
@@ -30,9 +30,7 @@ $RUNTIME_NOSETUPFS=true;
 require_once('../../../lib/base.php');
 OC_JSON::checkAppEnabled('media');
 
-if(defined("DEBUG") && DEBUG) {error_log($_GET['autoupdate']);}
 $autoUpdate=(isset($_GET['autoupdate']) and $_GET['autoupdate']=='true');
-if(defined("DEBUG") && DEBUG) {error_log((integer)$autoUpdate);}
 
 OC_Preferences::setValue(OC_User::getUser(),'media','autoupdate',(integer)$autoUpdate);
 
diff --git a/apps/media/lib_ampache.php b/apps/media/lib_ampache.php
index 87291958af..0ad84d6680 100644
--- a/apps/media/lib_ampache.php
+++ b/apps/media/lib_ampache.php
@@ -195,7 +195,6 @@ class OC_MEDIA_AMPACHE{
 		$filter=isset($params['filter'])?$params['filter']:'';
 		$exact=isset($params['exact'])?($params['exact']=='true'):false;
 		$artists=OC_MEDIA_COLLECTION::getArtists($filter,$exact);
-		if(defined("DEBUG") && DEBUG) {error_log('artists found: '.print_r($artists,true));}
 		echo('<root>');
 		foreach($artists as $artist){
 			self::printArtist($artist);
diff --git a/apps/media/lib_media.php b/apps/media/lib_media.php
index 7a666be8c2..485d616e1a 100644
--- a/apps/media/lib_media.php
+++ b/apps/media/lib_media.php
@@ -40,7 +40,6 @@ class OC_MEDIA{
 	 */
 	public static function loginListener($params){
 		if(isset($_POST['user']) and $_POST['password']){
-			if(defined("DEBUG") && DEBUG) {error_log('postlogin');}
 			$name=$_POST['user'];
 			$query=OC_DB::prepare("SELECT user_id from *PREFIX*media_users WHERE user_id LIKE ?");
 			$uid=$query->execute(array($name))->fetchAll();
@@ -64,7 +63,6 @@ class OC_MEDIA{
 			$path=substr($path,1);
 		}
 		$path='/'.$path;
-		error_log("$path was updated");
 		OC_MEDIA_SCANNER::scanFile($path);
 	}
 
diff --git a/apps/media/lib_scanner.php b/apps/media/lib_scanner.php
index 9bf9397b19..ef63cea45d 100644
--- a/apps/media/lib_scanner.php
+++ b/apps/media/lib_scanner.php
@@ -97,25 +97,25 @@ class OC_MEDIA_SCANNER{
 			$data=@self::$getID3->analyze($file);
 			getid3_lib::CopyTagsToComments($data);
 			if(!isset($data['comments'])){
-				if(defined("DEBUG") && DEBUG) {error_log("error reading id3 tags in '$file'");}
+				OC_Log::write('media',"error reading id3 tags in '$file'",OC_Log::WARN);
 				return;
 			}
 			if(!isset($data['comments']['artist'])){
-				if(defined("DEBUG") && DEBUG) {error_log("error reading artist tag in '$file'");}
+				OC_Log::write('media',"error reading artist tag in '$file'",OC_Log::WARN);
 				$artist='unknown';
 			}else{
 				$artist=stripslashes($data['comments']['artist'][0]);
 				$artist=utf8_encode($artist);
 			}
 			if(!isset($data['comments']['album'])){
-				if(defined("DEBUG") && DEBUG) {error_log("error reading album tag in '$file'");}
+				OC_Log::write('media',"error reading album tag in '$file'",OC_Log::WARN);
 				$album='unknown';
 			}else{
 				$album=stripslashes($data['comments']['album'][0]);
 				$album=utf8_encode($album);
 			}
 			if(!isset($data['comments']['title'])){
-				if(defined("DEBUG") && DEBUG) {error_log("error reading title tag in '$file'");}
+				OC_Log::write('media',"error reading title tag in '$file'",OC_Log::WARN);
 				$title='unknown';
 			}else{
 				$title=stripslashes($data['comments']['title'][0]);
diff --git a/apps/media/server/xml.server.php b/apps/media/server/xml.server.php
index 44a16793bf..2d54c863c7 100644
--- a/apps/media/server/xml.server.php
+++ b/apps/media/server/xml.server.php
@@ -37,7 +37,7 @@ foreach($arguments as &$argument){
 }
 ob_clean();
 if(isset($arguments['action'])){
-	if(defined("DEBUG") && DEBUG) {error_log($arguments['action']);}
+	OC_Log::write('media','ampache '.$arguments['action'].' request', OC_Log::DEBUG);
 	switch($arguments['action']){
 		case 'url_to_song':
 			OC_MEDIA_AMPACHE::url_to_song($arguments);
diff --git a/apps/remoteStorage/lib_remoteStorage.php b/apps/remoteStorage/lib_remoteStorage.php
index 5677ab3c6e..f10a72870a 100644
--- a/apps/remoteStorage/lib_remoteStorage.php
+++ b/apps/remoteStorage/lib_remoteStorage.php
@@ -7,7 +7,7 @@ class OC_remoteStorage {
 		if( PEAR::isError($result)) {
 			$entry = 'DB Error: "'.$result->getMessage().'"<br />';
 			$entry .= 'Offending command was: '.$result->getDebugInfo().'<br />';
-			if(defined("DEBUG") && DEBUG) {error_log( $entry );}
+			OC_Log::write('removeStorage',$entry,OC_Log::ERROR);
 			die( $entry );
 		}
 		$ret = array();
@@ -24,7 +24,7 @@ class OC_remoteStorage {
 		if( PEAR::isError($result)) {
 			$entry = 'DB Error: "'.$result->getMessage().'"<br />';
 			$entry .= 'Offending command was: '.$result->getDebugInfo().'<br />';
-			if(defined("DEBUG") && DEBUG) {error_log( $entry );}
+			OC_Log::write('removeStorage',$entry,OC_Log::ERROR);
 			die( $entry );
 		}
 		$ret = array();
@@ -45,7 +45,7 @@ class OC_remoteStorage {
 		if( PEAR::isError($result)) {
 			$entry = 'DB Error: "'.$result->getMessage().'"<br />';
 			$entry .= 'Offending command was: '.$result->getDebugInfo().'<br />';
-			if(defined("DEBUG") && DEBUG) {error_log( $entry );}
+			OC_Log::write('removeStorage',$entry,OC_Log::ERROR);
 			die( $entry );
 		}
 	}
@@ -56,7 +56,7 @@ class OC_remoteStorage {
 		if( PEAR::isError($result)) {
 			$entry = 'DB Error: "'.$result->getMessage().'"<br />';
 			$entry .= 'Offending command was: '.$result->getDebugInfo().'<br />';
-			if(defined("DEBUG") && DEBUG) {error_log( $entry );}
+			OC_Log::write('removeStorage',$entry,OC_Log::ERROR);
 			die( $entry );
 		}
 	}
diff --git a/apps/user_openid/appinfo/app.php b/apps/user_openid/appinfo/app.php
index 546f9f4565..912019a970 100644
--- a/apps/user_openid/appinfo/app.php
+++ b/apps/user_openid/appinfo/app.php
@@ -26,14 +26,14 @@ OC_User::useBackend('openid');
 
 //check for results from openid requests
 if(isset($_GET['openid_mode']) and $_GET['openid_mode'] == 'id_res'){
-	if(defined("DEBUG") && DEBUG) {error_log('openid retured');}
+	OC_Log::write('user_openid','openid retured',OC_Log::DEBUG);
 	$openid = new SimpleOpenID;
 	$openid->SetIdentity($_GET['openid_identity']);
 	$openid_validation_result = $openid->ValidateWithServer();
 	if ($openid_validation_result == true){         // OK HERE KEY IS VALID
-		if(defined("DEBUG") && DEBUG) {error_log('auth sucessfull');}
+		OC_Log::write('user_openid','auth sucessfull',OC_Log::DEBUG);
 		$identity=$openid->GetIdentity();
-		if(defined("DEBUG") && DEBUG) {error_log("auth as $identity");}
+		OC_Log::write('user_openid','auth as '.$identity,OC_Log::DEBUG);
 		$user=OC_USER_OPENID::findUserForIdentity($identity);
 		if($user){
 			$_SESSION['user_id']=$user;
@@ -41,13 +41,13 @@ if(isset($_GET['openid_mode']) and $_GET['openid_mode'] == 'id_res'){
 		}
 	}else if($openid->IsError() == true){            // ON THE WAY, WE GOT SOME ERROR
 		$error = $openid->GetError();
-		if(defined("DEBUG") && DEBUG) {error_log("ERROR CODE: " . $error['code']);}
-		if(defined("DEBUG") && DEBUG) {error_log("ERROR DESCRIPTION: " . $error['description']);}
+		OC_Log::write('user_openid','ERROR CODE: '. $error['code'],OC_Log::ERROR);
+		OC_Log::write('user_openid','ERROR DESCRIPTION: '. $error['description'],OC_Log::ERROR);
 	}else{                                            // Signature Verification Failed
-		if(defined("DEBUG") && DEBUG) {error_log("INVALID AUTHORIZATION");}
+		OC_Log::write('user_openid','INVALID AUTHORIZATION',OC_Log::ERROR);
 	}
 }else if (isset($_GET['openid_mode']) and $_GET['openid_mode'] == 'cancel'){ // User Canceled your Request
-	if(defined("DEBUG") && DEBUG) {error_log("USER CANCELED REQUEST");}
+	OC_Log::write('user_openid','USER CANCELED REQUEST',OC_Log::DEBUG);
 	return false;
 }
 
diff --git a/apps/user_openid/phpmyid.php b/apps/user_openid/phpmyid.php
index 5009fa410a..d8168c9a10 100644
--- a/apps/user_openid/phpmyid.php
+++ b/apps/user_openid/phpmyid.php
@@ -1053,8 +1053,6 @@ function debug ($x, $m = null) {
 	} else {
 		$x .= "\n";
 	}
-
-	if(defined("DEBUG") && DEBUG) {error_log($x . "\n", 3, $profile['logfile']);}
 }
 
 
@@ -1513,7 +1511,6 @@ function wrap_html ( $message ) {
 </body>
 </html>
 ';
-	if(defined("DEBUG") && DEBUG) {error_log($html);}
 	echo $html;
 	exit(0);
 }
@@ -1658,15 +1655,6 @@ $profile['req_url'] = sprintf("%s://%s%s",
 // 		      $port,//host  already includes the path
 		      $_SERVER["REQUEST_URI"]);
 
-// $fullId='user.php/'.$USERNAME.'/';
-// $incompleteId='user.php/';
-
-// if(!strpos($profile['req_url'],$fullId)){
-// 	$profile['req_url']=str_replace($incompleteId,$fullId,$profile['req_url']);
-// }
-
-// if(defined("DEBUG") && DEBUG) {error_log('inc id: '.$fullId);}
-// if(defined("DEBUG") && DEBUG) {error_log('req url: '.$profile['req_url']);}
 
 // Set the default allowance for testing
 if (! array_key_exists('allow_test', $profile))
diff --git a/apps/user_openid/user.php b/apps/user_openid/user.php
index 3cbc38491c..a267e02050 100644
--- a/apps/user_openid/user.php
+++ b/apps/user_openid/user.php
@@ -40,7 +40,7 @@ require_once '../../lib/base.php';
 OC_Util::checkAppEnabled('user_openid');
 
 if(!OC_User::userExists($USERNAME)){
-	if(defined("DEBUG") && DEBUG) {error_log($USERNAME.' doesn\'t exist');}
+	OC_Log::write('user_openid',$USERNAME.' doesn\'t exist',OC_Log::WARN);
 	$USERNAME='';
 }
 $IDENTITY=OC_Helper::linkTo( "user_openid", "user.php", null, true ).'/'.$USERNAME;
diff --git a/files/ajax/newfolder.php b/files/ajax/newfolder.php
index 43d87461fc..6966e912c5 100644
--- a/files/ajax/newfolder.php
+++ b/files/ajax/newfolder.php
@@ -13,7 +13,7 @@ if($foldername == '') {
 	OC_JSON::error(array("data" => array( "message" => "Empty Foldername" )));
 	exit();
 }
-if(defined("DEBUG") && DEBUG) {error_log('try to create ' . $foldername . ' in ' . $dir);}
+
 if(OC_Files::newFile($dir, $foldername, 'dir')) {
 	OC_JSON::success(array("data" => array()));
 	exit();
diff --git a/index.php b/index.php
index 924e7394f7..558733e1cd 100644
--- a/index.php
+++ b/index.php
@@ -31,7 +31,7 @@ if($not_installed) {
 	// Check for autosetup:
 	$autosetup_file = OC::$SERVERROOT."/config/autoconfig.php";
 	if( file_exists( $autosetup_file )){
-		error_log("Autoconfig file found, setting up owncloud...");
+		OC_Log::write('core','Autoconfig file found, setting up owncloud...',OC_Log::INFO);
 		include( $autosetup_file );
 		$_POST['install'] = 'true';
 		$_POST = array_merge ($_POST, $AUTOCONFIG);
@@ -68,7 +68,7 @@ else {
 	// remember was checked after last login
 	if(isset($_COOKIE["oc_remember_login"]) && isset($_COOKIE["oc_token"]) && isset($_COOKIE["oc_username"]) && $_COOKIE["oc_remember_login"]) {
 		if(defined("DEBUG") && DEBUG) {
-			error_log("Trying to login from cookie");
+			OC_Log::write('core','Trying to login from cookie',OC_Log::DEBUG);
 		}
 		// confirm credentials in cookie
 		if(isset($_COOKIE['oc_token']) && OC_User::userExists($_COOKIE['oc_username']) &&
@@ -86,7 +86,7 @@ else {
 		if(OC_User::login($_POST["user"], $_POST["password"])) {
 			if(!empty($_POST["remember_login"])){
 				if(defined("DEBUG") && DEBUG) {
-					error_log("Setting remember login to cookie");
+					OC_Log::write('core','Setting remember login to cookie',OC_Log::DEBUG);
 				}
 				$token = md5($_POST["user"].time());
 				OC_Preferences::setValue($_POST['user'], 'login', 'token', $token);
diff --git a/lib/db.php b/lib/db.php
index ef6d1dcc8b..fa3995be12 100644
--- a/lib/db.php
+++ b/lib/db.php
@@ -161,9 +161,8 @@ class OC_DB {
 			// Die if we could not connect
 			if( PEAR::isError( self::$MDB2 )){
 				echo( '<b>can not connect to database, using '.$type.'. ('.self::$MDB2->getUserInfo().')</center>');
-				$error = self::$MDB2->getMessage();
-				error_log( $error);
-				error_log( self::$MDB2->getUserInfo());
+				OC_Log::write('core',self::$MDB2->getUserInfo(),OC_Log::FATAL);
+				OC_Log::write('core',self::$MDB2->getMessage(),OC_Log::FATAL);
 				die( $error );
 			}
 			
@@ -195,7 +194,7 @@ class OC_DB {
 			if( PEAR::isError($result)) {
 				$entry = 'DB Error: "'.$result->getMessage().'"<br />';
 				$entry .= 'Offending command was: '.$query.'<br />';
-				error_log( $entry );
+				OC_Log::write('core',$entry,OC_Log::FATAL);
 				die( $entry );
 			}
 		}else{
@@ -204,7 +203,7 @@ class OC_DB {
 			}catch(PDOException $e){
 				$entry = 'DB Error: "'.$e->getMessage().'"<br />';
 				$entry .= 'Offending command was: '.$query.'<br />';
-				error_log( $entry );
+				OC_Log::write('core',$entry,OC_Log::FATAL);
 				die( $entry );
 			}
 			$result=new PDOStatementWrapper($result);
diff --git a/lib/filestorage/local.php b/lib/filestorage/local.php
index 180b056f34..8e0907f8d3 100644
--- a/lib/filestorage/local.php
+++ b/lib/filestorage/local.php
@@ -195,7 +195,6 @@ class OC_Filestorage_Local extends OC_Filestorage{
 	}
 
 	private function delTree($dir) {
-		if(defined("DEBUG") && DEBUG) {error_log('del'.$dir);}
 		$dirRelative=$dir;
 		$dir=$this->datadir.$dir;
 		if (!file_exists($dir)) return true;
diff --git a/lib/installer.php b/lib/installer.php
index 0febb2cab4..242ca97934 100644
--- a/lib/installer.php
+++ b/lib/installer.php
@@ -56,7 +56,7 @@ class OC_Installer{
 	 */
 	public static function installApp( $data = array()){
 		if(!isset($data['source'])){
-			if(defined("DEBUG") && DEBUG) {error_log("No source specified when installing app");}
+			OC_Log::write('core','No source specified when installing app',OC_Log::ERROR);
 			return false;
 		}
 		
@@ -64,13 +64,13 @@ class OC_Installer{
 		if($data['source']=='http'){
 			$path=tempnam(sys_get_temp_dir(),'oc_installer_');
 			if(!isset($data['href'])){
-				if(defined("DEBUG") && DEBUG) {error_log("No href specified when installing app from http");}
+				OC_Log::write('core','No href specified when installing app from http',OC_Log::ERROR);
 				return false;
 			}
 			copy($data['href'],$path);
 		}else{
 			if(!isset($data['path'])){
-				if(defined("DEBUG") && DEBUG) {error_log("No path specified when installing app from local file");}
+				OC_Log::write('core','No path specified when installing app from local file',OC_Log::ERROR);
 				return false;
 			}
 			$path=$data['path'];
@@ -85,7 +85,7 @@ class OC_Installer{
 			$zip->extractTo($extractDir);
 			$zip->close();
 		} else {
-			if(defined("DEBUG") && DEBUG) {error_log("Failed to open archive when installing app");}
+			OC_Log::write('core','Failed to open archive when installing app',OC_Log::ERROR);
 			OC_Helper::rmdirr($extractDir);
 			if($data['source']=='http'){
 				unlink($path);
@@ -95,7 +95,7 @@ class OC_Installer{
 		
 		//load the info.xml file of the app
 		if(!is_file($extractDir.'/appinfo/info.xml')){
-			if(defined("DEBUG") && DEBUG) {error_log("App does not provide an info.xml file");}
+			OC_Log::write('core','App does not provide an info.xml file',OC_Log::ERROR);
 			OC_Helper::rmdirr($extractDir);
 			if($data['source']=='http'){
 				unlink($path);
@@ -107,7 +107,7 @@ class OC_Installer{
 		
 		//check if an app with the same id is already installed
 		if(self::isInstalled( $info['id'] )){
-			if(defined("DEBUG") && DEBUG) {error_log("App already installed");}
+			OC_Log::write('core','App already installed',OC_Log::WARN);
 			OC_Helper::rmdirr($extractDir);
 			if($data['source']=='http'){
 				unlink($path);
@@ -117,7 +117,7 @@ class OC_Installer{
 
 		//check if the destination directory already exists
 		if(is_dir($basedir)){
-			if(defined("DEBUG") && DEBUG) {error_log("App's directory already exists");}
+			OC_Log::write('core','App directory already exists',OC_Log::WARN);
 			OC_Helper::rmdirr($extractDir);
 			if($data['source']=='http'){
 				unlink($path);
@@ -131,7 +131,7 @@ class OC_Installer{
 		
 		//copy the app to the correct place
 		if(!mkdir($basedir)){
-			if(defined("DEBUG") && DEBUG) {error_log('Can\'t create app folder ('.$basedir.')');}
+			OC_Log::write('core','Can\'t create app folder ('.$basedir.')',OC_Log::ERROR);
 			OC_Helper::rmdirr($extractDir);
 			if($data['source']=='http'){
 				unlink($path);
diff --git a/lib/preferences.php b/lib/preferences.php
index 6d8aa17afd..75201f455b 100644
--- a/lib/preferences.php
+++ b/lib/preferences.php
@@ -140,7 +140,6 @@ class OC_Preferences{
 		// Check if the key does exist
 		$query = OC_DB::prepare( 'SELECT configvalue FROM *PREFIX*preferences WHERE userid = ? AND appid = ? AND configkey = ?' );
 		$values=$query->execute(array($user,$app,$key))->fetchAll();
-		if(defined("DEBUG") && DEBUG) {error_log(print_r($values,true));}
 		$exists=(count($values)>0);
 
 		if( !$exists ){