CIMDisk::SetStorageId

static function SetStorageId($id)
{
	$id = (int)$id;
	if ($id <= 0)
	{
		return false;
	}

	$oldId = self::GetStorageId();
	if ($oldId > 0 && $oldId != $id)
	{
		$connection = BitrixMainApplication::getConnection();
		$connection->queryExecute("UPDATE b_im_chat SET DISK_FOLDER_ID = 0");
		$connection->queryExecute("DELETE FROM b_im_message_param WHERE PARAM_NAME = 'FILE_ID'");
	}

	BitrixMainConfigOption::set('im', 'disk_storage_id', $id);

	return true;
}