diff --git a/core/config.class.inc.php b/core/config.class.inc.php
index 3e9dcd7d2..c18bdd5c2 100644
--- a/core/config.class.inc.php
+++ b/core/config.class.inc.php
@@ -2071,7 +2071,6 @@ class Config
 			$bReturn = fclose($hFile);
 
 			utils::SetConfig($this);
-			FileLog::RenameLegacyLogFiles();
 
 			return $bReturn;
 		}
diff --git a/core/log.class.inc.php b/core/log.class.inc.php
index e9a505de5..be2b198f0 100644
--- a/core/log.class.inc.php
+++ b/core/log.class.inc.php
@@ -18,24 +18,36 @@
 
 
 /**
- * @since 2.7.0 N°2518
+ * @since 2.7.0 N°2518 N°2793
  */
-interface ILogFileNameBuilder
+interface iLogFileNameBuilder
 {
-	public function __construct($sFileFullPath);
+	/**
+	 * @param string $sLogFileFullPath full path name for the log file
+	 */
+	public function __construct($sLogFileFullPath = null);
 
+	/**
+	 * @return string log file path we will write new log entry to
+	 */
 	public function GetLogFilePath();
 }
 
-class DefaultLogFileNameBuilder implements ILogFileNameBuilder
+class DefaultLogFileNameBuilder implements iLogFileNameBuilder
 {
 	private $sLogFileFullPath;
 
-	public function __construct($sFileFullPath)
+	/**
+	 * @inheritDoc
+	 */
+	public function __construct($sLogFileFullPath = null)
 	{
-		$this->sLogFileFullPath = $sFileFullPath;
+		$this->sLogFileFullPath = $sLogFileFullPath;
 	}
 
+	/**
+	 * @inheritDoc
+	 */
 	public function GetLogFilePath()
 	{
 		return $this->sLogFileFullPath;
@@ -45,60 +57,278 @@ class DefaultLogFileNameBuilder implements ILogFileNameBuilder
 /**
  * Adds a suffix to the filename
  *
- * @since 2.7.0 N°2518
+ * @since 2.7.0 N°2518 N°2793
  */
-abstract class RotatingLogFileNameBuilder implements ILogFileNameBuilder
+abstract class RotatingLogFileNameBuilder implements iLogFileNameBuilder
 {
+	/**
+	 * Test is done each time to cover edge case like session beginning at 23:59 and ending at 00:01
+	 * We are caching the file mtime though
+	 * @var array with full file path as key and DateTime (file last modification time) as value
+	 */
+	protected static $aLogFileLastModified = array();
+	/** @var string */
+	protected $sLogFileFullPath;
+	/** @var string */
 	protected $sFilePath;
+	/** @var string */
 	protected $sFileBaseName;
+	/** @var string */
 	protected $sFileExtension;
 
-	public function __construct($sFileFullPath)
+	/**
+	 * @inheritDoc
+	 */
+	public function __construct($sLogFileFullPath = null)
 	{
-		$aPathParts = pathinfo($sFileFullPath);
+		$this->sLogFileFullPath = $sLogFileFullPath;
+	}
 
+	protected function GetLastModifiedDateForFile()
+	{
+		if (isset(static::$aLogFileLastModified[$this->sLogFileFullPath]))
+		{
+			return static::$aLogFileLastModified[$this->sLogFileFullPath];
+		}
+
+		return null;
+	}
+
+	protected function SetLastModifiedDateForFile($oDateTime)
+	{
+		static::$aLogFileLastModified[$this->sLogFileFullPath] = $oDateTime;
+	}
+
+	/**
+	 * Need to be called when the file is rotated : actually the next call will need to check on the real date modified instead of using
+	 * the previously  cached value !
+	 */
+	public function ResetLastModifiedDateForFile()
+	{
+		static::$aLogFileLastModified[$this->sLogFileFullPath] = null;
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * Doing the check before opening and writing the log file. There is also a iProcess but cron can be disabled...
+	 *
+	 * @see \LogFileRotationProcess the iProcess impl
+	 */
+	public function GetLogFilePath()
+	{
+		$this->CheckAndRotateLogFile();
+		return $this->sLogFileFullPath;
+	}
+
+	/**
+	 * Check log last date modified. If too old then rotate the log file (move it to a new name with a suffix)
+	 *
+	 * @uses filemtime() to get log file date last modified
+	 */
+	public function CheckAndRotateLogFile()
+	{
+		if ($this->GetLastModifiedDateForFile() === null)
+		{
+			if ($this->IsLogFileExists())
+			{
+				return;
+			}
+
+			$iLogDateLastModifiedTimeStamp = filemtime($this->sLogFileFullPath);
+			if ($iLogDateLastModifiedTimeStamp === false)
+			{
+				return;
+			}
+			$this->SetLastModifiedDateForFile(DateTime::createFromFormat('U', $iLogDateLastModifiedTimeStamp));
+		}
+
+		$oNow = new DateTime();
+		$bShouldRotate = $this->ShouldRotate($this->GetLastModifiedDateForFile(), $oNow);
+		if (!$bShouldRotate)
+		{
+			return;
+		}
+
+		$this->RotateLogFile($this->GetLastModifiedDateForFile());
+	}
+
+	/**
+	 * Rotate current log file
+	 *
+	 * @param DateTime $oLogFileLastModified date when the log file was last modified
+	 *
+	 * @uses \iTopMutex instead of flock as doing a rename on a file with a flock cause an error on PHP 5.6.40 Windows (ok on 7.3.15 though)
+	 * @uses GetRotatedFileName to get rotated file name
+	 */
+	protected function RotateLogFile($oLogFileLastModified)
+	{
+		if (!$this->IsLogFileExists()) // extra check, but useful for cron also !
+		{
+			return;
+		}
+
+		$oLock = null;
+		try
+		{
+			$oLock = new iTopMutex('log_rotation_'.$this->sLogFileFullPath);
+			$oLock->Lock();
+			$this->ResetLastModifiedDateForFile();
+			$sNewLogFileName = $this->GetRotatedFileName($oLogFileLastModified);
+			rename($this->sLogFileFullPath, $sNewLogFileName);
+		}
+		catch (Exception $e)
+		{
+			// nothing to do, cannot log... file will be renamed on the next call O:)
+			return;
+		}
+		finally
+		{
+			if (!is_null($oLock)) { $oLock->Unlock();}
+		}
+	}
+
+	/**
+	 * @param DateTime $oLogFileLastModified date when the log file was last modified
+	 *
+	 * @return string the full path of the rotated log file
+	 * @uses static::$oLogFileLastModified
+	 * @uses GetFileSuffix
+	 */
+	protected function GetRotatedFileName($oLogFileLastModified)
+	{
+		$aPathParts = pathinfo($this->sLogFileFullPath);
 		$this->sFilePath = $aPathParts['dirname'];
 		$this->sFileBaseName = $aPathParts['filename'];
 		$this->sFileExtension = $aPathParts['extension'];
-	}
 
-	public function GetLogFilePath()
-	{
-		$sFileSuffix = $this->GetFileSuffix();
+		$sFileSuffix = $this->GetFileSuffix($oLogFileLastModified);
 
-		return $this->sFilePath
-			.'/'
+		return $this->sFilePath.DIRECTORY_SEPARATOR
 			.$this->sFileBaseName
 			.'.'.$sFileSuffix
 			.'.'.$this->sFileExtension;
 	}
 
-	abstract protected function GetFileSuffix();
+	/**
+	 * @return bool
+	 */
+	public function IsLogFileExists()
+	{
+		return !file_exists($this->sLogFileFullPath) || !is_readable($this->sLogFileFullPath);
+	}
+
+	/**
+	 * @param DateTime $oLogFileLastModified date when the log file was last modified
+	 * @param DateTime $oNow date/time of the log we want to write
+	 *
+	 * @return bool true if the file has older informations and we need to move it to an archive (rotate), false if we don't have to
+	 */
+	abstract public function ShouldRotate($oLogFileLastModified, $oNow);
+
+	/**
+	 * @param DateTime $oDate log file last modification date
+	 *
+	 * @return string suffix for the rotated log file
+	 */
+	abstract protected function GetFileSuffix($oDate);
+
+	/**
+	 * @see \LogFileRotationProcess
+	 *
+	 * @param \DateTime $oNow current date
+	 *
+	 * @return DateTime time when the cron process should run
+	 */
+	abstract public function GetCronProcessNextOccurrence(DateTime $oNow);
 }
 
 /**
- * @since 2.7.0 N°2518
+ * @since 2.7.0 N°2518 N°2793
  */
 class DailyRotatingLogFileNameBuilder extends RotatingLogFileNameBuilder
 {
-	protected function GetFileSuffix()
+	/**
+	 * @inheritDoc
+	 */
+	protected function GetFileSuffix($oDate)
 	{
-		return date('Y-m-d');
+		return $oDate->format('Y-m-d');
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function ShouldRotate($oLogFileLastModified, $oNow)
+	{
+		$oInterval = $oNow->diff($oLogFileLastModified);
+		$iDaysDiff = $oInterval->d;
+
+		return $iDaysDiff > 0;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function GetCronProcessNextOccurrence(DateTime $oNow)
+	{
+		$oOccurrence = clone $oNow;
+		$oOccurrence->modify('tomorrow');
+
+		return $oOccurrence;
 	}
 }
 
 /**
- * @since 2.7.0 N°2518
+ * @since 2.7.0 N°2518 N°2793
  */
 class WeeklyRotatingLogFileNameBuilder extends RotatingLogFileNameBuilder
 {
-	protected function GetFileSuffix()
+	/**
+	 * @inheritDoc
+	 */
+	protected function GetFileSuffix($oDate)
 	{
-		$sWeekYear = date('o');
-		$sWeekNumber = date('W');
+		$sWeekYear = $oDate->format('o');
+		$sWeekNumber = $oDate->format('W');
 
 		return $sWeekYear.'-week'.$sWeekNumber;
 	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function ShouldRotate($oLogFileLastModified, $oNow)
+	{
+		$iLogYear = $oLogFileLastModified->format('Y');
+		$iLogWeek = $oLogFileLastModified->format('W');
+		$iNowYear = $oNow->format('Y');
+		$iNowWeek = $oNow->format('W');
+
+		if ($iLogYear !== $iNowYear)
+		{
+			return true;
+		}
+
+		if ($iLogWeek !== $iNowWeek)
+		{
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function GetCronProcessNextOccurrence(DateTime $oNow)
+	{
+		$oOccurrence = clone $oNow;
+		$oOccurrence->modify('Monday next week');
+		$oOccurrence->setTime(0, 0, 0);
+
+		return $oOccurrence;
+	}
 }
 
 /**
@@ -111,7 +341,7 @@ class LogFileNameBuilderFactory
 	 *
 	 * @param string $sFileFullPath
 	 *
-	 * @return \ILogFileNameBuilder
+	 * @return \iLogFileNameBuilder
 	 * @throws \ConfigException
 	 * @throws \CoreException
 	 */
@@ -119,7 +349,7 @@ class LogFileNameBuilderFactory
 	{
 		$oConfig = utils::GetConfig();
 		$sFileNameBuilderImpl = $oConfig->Get('log_filename_builder_impl');
-		if (empty($sFileNameBuilderImpl) || !class_exists($sFileNameBuilderImpl))
+		if (!is_a($sFileNameBuilderImpl, iLogFileNameBuilder::class, true))
 		{
 			$sFileNameBuilderImpl = 'DefaultLogFileNameBuilder';
 		}
@@ -134,7 +364,7 @@ class LogFileNameBuilderFactory
  *
  * @copyright   Copyright (C) 2010-2017 Combodo SARL
  * @license     http://opensource.org/licenses/AGPL-3.0
- * @since 2.7.0 allow to rotate file (N°2518)
+ * @since 2.7.0 N°2518 N°2793 file log rotation
  */
 class FileLog
 {
@@ -153,52 +383,6 @@ class FileLog
 		$this->oFileNameBuilder = LogFileNameBuilderFactory::GetInstance($sFileName);
 	}
 
-	/**
-	 * Since 2.7.0 with the 'log_filename_builder_impl' param the logs will output to different files name
-	 * As now by default iTop will use {@link WeeklyRotatingLogFileNameBuilder} (rotation each week), to avoid confusion, we're renaming
-	 * the legacy error.log / setup.log.
-	 *
-	 * @since 2.7.0 N°2518
-	 * @uses utils::GetConfig() the config must be persisted !
-	 */
-	public static function RenameLegacyLogFiles()
-	{
-		$oConfig = utils::GetConfig();
-		IssueLog::Enable(APPROOT.'log/error.log'); // refresh log file used
-		$sLogFileNameParam = $oConfig->Get('log_filename_builder_impl');
-		$aConfigValuesNoRotation = array('', 'DefaultLogFileNameBuilder');
-
-		$bIsLogRotationActivated = (!in_array($sLogFileNameParam, $aConfigValuesNoRotation, true));
-		if (!$bIsLogRotationActivated)
-		{
-			return;
-		}
-
-		IssueLog::Warning("Log name builder set to '$sLogFileNameParam', renaming legacy log files");
-		$aLogFilesToRename = array(
-			'log/setup.log' => 'log/setup.LEGACY.log',
-			'log/error.log' => 'log/error.LEGACY.log',
-		);
-		foreach ($aLogFilesToRename as $sLogCurrentName => $sLogNewName)
-		{
-			$sSource = APPROOT.$sLogCurrentName;
-			if (!file_exists($sSource))
-			{
-				IssueLog::Debug("Log file '$sLogCurrentName' (legacy) does not exists, renaming skipped");
-				continue;
-			}
-
-			$sDestination = APPROOT.$sLogNewName;
-			$bResult = rename($sSource, $sDestination);
-			if (!$bResult)
-			{
-				IssueLog::Error("Log file '$sLogCurrentName' (legacy) cannot be renamed to '$sLogNewName'");
-				continue;
-			}
-			IssueLog::Info("Log file '$sLogCurrentName' (legacy) renamed to '$sLogNewName'");
-		}
-	}
-
 	public function Error($sText, $sChannel = '', $aContext = array())
 	{
 		$this->Write($sText, __FUNCTION__, $sChannel, $aContext);
@@ -427,3 +611,72 @@ class ToolsLog extends LogAPI
 
 	protected static $m_oFileLog = null;
 }
+
+
+class LogFileRotationProcess implements iScheduledProcess
+{
+	/**
+	 * Cannot get this list from anywhere as log file name is provided by the caller using LogAPI::Enable
+	 * @var string[]
+	 */
+	const LOGFILES_TO_ROTATE = array(
+		'setup.log',
+		'error.log',
+		'tools.log',
+		'itop-fence.log',
+	);
+
+	/**
+	 * @inheritDoc
+	 */
+	public function Process($iUnixTimeLimit)
+	{
+		$sLogFileNameBuilder = $this->GetLogFileNameBuilderClassName();
+
+		foreach (self::LOGFILES_TO_ROTATE as $sLogFileName)
+		{
+			$sLogFileFullPath = APPROOT
+				.DIRECTORY_SEPARATOR.'log'
+				.DIRECTORY_SEPARATOR.$sLogFileName;
+
+			/** @var \RotatingLogFileNameBuilder $oLogFileNameBuilder */
+			$oLogFileNameBuilder = new $sLogFileNameBuilder($sLogFileFullPath);
+			$oLogFileNameBuilder->ResetLastModifiedDateForFile();
+			$oLogFileNameBuilder->CheckAndRotateLogFile();
+		}
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function GetNextOccurrence()
+	{
+		try
+		{
+			$sLogFileNameBuilder = $this->GetLogFileNameBuilderClassName();
+		}
+		catch (ProcessException $e)
+		{
+			return new DateTime('3000-01-01');
+		}
+
+		/** @var \RotatingLogFileNameBuilder $oLogFileNameBuilder */
+		$oLogFileNameBuilder = new $sLogFileNameBuilder();
+		return $oLogFileNameBuilder->GetCronProcessNextOccurrence(new DateTime());
+	}
+
+	/**
+	 * @return string RotatingLogFileNameBuilder implementation configured
+	 * @throws \ProcessException if the class is invalid
+	 */
+	private function GetLogFileNameBuilderClassName()
+	{
+		$sLogFileNameBuilder = MetaModel::GetConfig()->Get('log_filename_builder_impl');
+		if (is_a($sLogFileNameBuilder, RotatingLogFileNameBuilder::class, true))
+		{
+			return $sLogFileNameBuilder;
+		}
+
+		throw new ProcessException(self::class.' : The configured filename builder is invalid (log_filename_builder_impl="'.$sLogFileNameBuilder.'")');
+	}
+}
\ No newline at end of file
diff --git a/test/core/LogFileNameBuilderTest.php b/test/core/LogFileNameBuilderTest.php
new file mode 100644
index 000000000..d69baa968
--- /dev/null
+++ b/test/core/LogFileNameBuilderTest.php
@@ -0,0 +1,80 @@
+<?php
+
+
+namespace Combodo\iTop\Test\UnitTest\Core;
+
+
+use Combodo\iTop\Test\UnitTest\ItopTestCase;
+use DailyRotatingLogFileNameBuilder;
+use DateTime;
+use WeeklyRotatingLogFileNameBuilder;
+
+class LogFileNameBuilderTest extends ItopTestCase
+{
+	public function ShouldRotateProvider()
+	{
+		return array(
+			'WEEKLY Same week' => array('WeeklyRotatingLogFileNameBuilder', '2020-02-01 00:00', '2020-02-01 00:00', false),
+			'WEEKLY 1 week diff, same month' => array('WeeklyRotatingLogFileNameBuilder', '2020-02-01 00:00', '2020-02-08 00:00', true),
+			'WEEKLY 2 weeks diff, same month' => array('WeeklyRotatingLogFileNameBuilder', '2020-02-01 00:00', '2020-02-15 00:00', true),
+			'WEEKLY 1 week diff, different month' => array('WeeklyRotatingLogFileNameBuilder', '2020-01-27 00:00', '2020-02-03 00:00', true),
+			'WEEKLY same week, different month' => array('WeeklyRotatingLogFileNameBuilder', '2020-01-27 00:00', '2020-02-02 00:00', false),
+			'WEEKLY 1 week diff, different year' => array('WeeklyRotatingLogFileNameBuilder', '2019-12-30 00:00', '2020-01-06 00:00', true),
+			'WEEKLY same week, different year' => array('WeeklyRotatingLogFileNameBuilder', '2019-12-30 00:00', '2020-01-05 00:00', true),
+			'DAILY Same day' => array('DailyRotatingLogFileNameBuilder', '2020-02-01 00:00', '2020-02-01 15:42', false),
+			'DAILY Same week, different day' => array('DailyRotatingLogFileNameBuilder', '2020-02-01 00:00', '2020-02-02 00:00', true),
+			'DAILY 1 week diff' => array('DailyRotatingLogFileNameBuilder', '2020-02-01 00:00', '2020-02-08 00:00', true),
+		);
+	}
+
+	/**
+	 * @param string $sFileNameBuilderClass RotatingLogFileNameBuilder impl
+	 * @param string $sDateModified format Y-m-d H:i
+	 * @param string $sDateNow format Y-m-d H:i
+	 * @param bool $bExpected
+	 *
+	 * @dataProvider ShouldRotateProvider
+	 */
+	public function testShouldRotate($sFileNameBuilderClass, $sDateModified, $sDateNow, $bExpected)
+	{
+		$oDateModified = DateTime::createFromFormat('Y-m-d H:i', $sDateModified);
+		$oDateNow = DateTime::createFromFormat('Y-m-d H:i', $sDateNow);
+
+		/** @var \RotatingLogFileNameBuilder $oFileBuilder */
+		$oFileBuilder = new $sFileNameBuilderClass();
+		$bShouldRotate = $oFileBuilder->ShouldRotate($oDateModified, $oDateNow);
+
+		$this->assertEquals($bExpected, $bShouldRotate);
+	}
+
+	public function CronNextOccurrenceProvider()
+	{
+		return array(
+			'DAILY morning' => array('DailyRotatingLogFileNameBuilder', '2020-02-01 05:00', '2020-02-02 00:00'),
+			'DAILY midnight' => array('DailyRotatingLogFileNameBuilder', '2020-02-01 00:00', '2020-02-02 00:00'),
+			'WEEKLY monday 12:42' => array('WeeklyRotatingLogFileNameBuilder', '2020-02-03 12:42', '2020-02-10 00:00'),
+			'WEEKLY monday 00:00' => array('WeeklyRotatingLogFileNameBuilder', '2020-02-03 00:00', '2020-02-10 00:00'),
+			'WEEKLY tuesday 12:42' => array('WeeklyRotatingLogFileNameBuilder', '2020-02-04 12:42', '2020-02-10 00:00'),
+			'WEEKLY sunday 12:42' => array('WeeklyRotatingLogFileNameBuilder', '2020-02-02 12:42', '2020-02-03 00:00'),
+		);
+	}
+
+	/**
+	 * @param string $sFileNameBuilderClass RotatingLogFileNameBuilder impl
+	 * @param string $sDateNow format Y-m-d H:i
+	 * @param string $sExpectedOccurrence format Y-m-d H:i
+	 *
+	 * @dataProvider CronNextOccurrenceProvider
+	 */
+	public function testCronNextOccurrence($sFileNameBuilderClass, $sDateNow, $sExpectedOccurrence)
+	{
+		$oDateNow = DateTime::createFromFormat('Y-m-d H:i', $sDateNow);
+
+		/** @var \RotatingLogFileNameBuilder $oFileBuilder */
+		$oFileBuilder = new $sFileNameBuilderClass();
+		$oActualOccurrence = $oFileBuilder->GetCronProcessNextOccurrence($oDateNow);
+		$sActualOccurrence = $oActualOccurrence->format('Y-m-d H:i');
+
+		$this->assertEquals($sExpectedOccurrence, $sActualOccurrence);
+	}
+}
\ No newline at end of file