diff --git a/admin/tool/generator/classes/backend.php b/admin/tool/generator/classes/backend.php
index 20b3370bd1f..da931db0f90 100644
--- a/admin/tool/generator/classes/backend.php
+++ b/admin/tool/generator/classes/backend.php
@@ -51,6 +51,11 @@ abstract class tool_generator_backend {
      */
     protected $fixeddataset;
 
+    /**
+     * @var int|bool Maximum number of bytes for file.
+     */
+    protected $filesizelimit;
+
     /**
      * @var bool True if displaying progress
      */
@@ -81,10 +86,11 @@ abstract class tool_generator_backend {
      *
      * @param int $size Size as numeric index
      * @param bool $fixeddataset To use fixed or random data
+     * @param int|bool $filesizelimit The max number of bytes for a generated file
      * @param bool $progress True if progress information should be displayed
      * @throws coding_exception If parameters are invalid
      */
-    public function __construct($size, $fixeddataset = false, $progress = true) {
+    public function __construct($size, $fixeddataset = false, $filesizelimit = false, $progress = true) {
 
         // Check parameter.
         if ($size < self::MIN_SIZE || $size > self::MAX_SIZE) {
@@ -94,6 +100,7 @@ abstract class tool_generator_backend {
         // Set parameters.
         $this->size = $size;
         $this->fixeddataset = $fixeddataset;
+        $this->filesizelimit = $filesizelimit;
         $this->progress = $progress;
     }
 
diff --git a/admin/tool/generator/classes/course_backend.php b/admin/tool/generator/classes/course_backend.php
index 07e1e7b1c85..1034b93bea0 100644
--- a/admin/tool/generator/classes/course_backend.php
+++ b/admin/tool/generator/classes/course_backend.php
@@ -100,15 +100,15 @@ class tool_generator_course_backend extends tool_generator_backend {
      * @param string $shortname Course shortname
      * @param int $size Size as numeric index
      * @param bool $fixeddataset To use fixed or random data
+     * @param int|bool $filesizelimit The max number of bytes for a generated file
      * @param bool $progress True if progress information should be displayed
-     * @return int Course id
      */
-    public function __construct($shortname, $size, $fixeddataset = false, $progress = true) {
+    public function __construct($shortname, $size, $fixeddataset = false, $filesizelimit = false, $progress = true) {
 
         // Set parameters.
         $this->shortname = $shortname;
 
-        parent::__construct($size, $fixeddataset, $progress);
+        parent::__construct($size, $fixeddataset, $filesizelimit, $progress);
     }
 
     /**
@@ -345,7 +345,7 @@ class tool_generator_course_backend extends tool_generator_backend {
 
             // Generate random binary data (different for each file so it
             // doesn't compress unrealistically).
-            $data = self::get_random_binary(self::$paramsmallfilesize[$this->size]);
+            $data = self::get_random_binary($this->limit_filesize(self::$paramsmallfilesize[$this->size]));
 
             $fs->create_file_from_string($filerecord, $data);
             $this->dot($i, $count);
@@ -362,6 +362,7 @@ class tool_generator_course_backend extends tool_generator_backend {
      * @return Random data
      */
     private static function get_random_binary($length) {
+
         $data = microtime(true);
         if (strlen($data) > $length) {
             // Use last digits of data.
@@ -382,8 +383,9 @@ class tool_generator_course_backend extends tool_generator_backend {
 
         // Work out how many files and how many blocks to use (up to 64KB).
         $count = self::$parambigfilecount[$this->size];
-        $blocks = ceil(self::$parambigfilesize[$this->size] / 65536);
-        $blocksize = floor(self::$parambigfilesize[$this->size] / $blocks);
+        $filesize = $this->limit_filesize(self::$parambigfilesize[$this->size]);
+        $blocks = ceil($filesize / 65536);
+        $blocksize = floor($filesize / $blocks);
 
         $this->log('createbigfiles', $count, true);
 
@@ -504,4 +506,20 @@ class tool_generator_course_backend extends tool_generator_backend {
         return $userid;
     }
 
+    /**
+     * Restricts the binary file size if necessary
+     *
+     * @param int $length The total length
+     * @return int The limited length if a limit was specified.
+     */
+    private function limit_filesize($length) {
+
+        // Limit to $this->filesizelimit.
+        if (is_numeric($this->filesizelimit) && $length > $this->filesizelimit) {
+            $length = floor($this->filesizelimit);
+        }
+
+        return $length;
+    }
+
 }
diff --git a/admin/tool/generator/classes/site_backend.php b/admin/tool/generator/classes/site_backend.php
index 9bf6a0c7ff1..b0f7f6851db 100644
--- a/admin/tool/generator/classes/site_backend.php
+++ b/admin/tool/generator/classes/site_backend.php
@@ -61,15 +61,16 @@ class tool_generator_site_backend extends tool_generator_backend {
      * @param int $size Size as numeric index
      * @param bool $bypasscheck If debugging level checking was skipped.
      * @param bool $fixeddataset To use fixed or random data
+     * @param int|bool $filesizelimit The max number of bytes for a generated file
      * @param bool $progress True if progress information should be displayed
      * @return int Course id
      */
-    public function __construct($size, $bypasscheck, $fixeddataset = false, $progress = true) {
+    public function __construct($size, $bypasscheck, $fixeddataset = false, $filesizelimit = false, $progress = true) {
 
         // Set parameters.
         $this->bypasscheck = $bypasscheck;
 
-        parent::__construct($size, $fixeddataset, $progress);
+        parent::__construct($size, $fixeddataset, $filesizelimit, $progress);
     }
 
     /**
@@ -148,6 +149,10 @@ class tool_generator_site_backend extends tool_generator_backend {
             $options[] = '--quiet';
         }
 
+        if ($this->filesizelimit) {
+            $options[] = '--filesizelimit="' . $this->filesizelimit . '"';
+        }
+
         // Extend options.
         $optionstoextend = array(
             'fixeddataset' => 'fixeddataset',
diff --git a/admin/tool/generator/cli/maketestcourse.php b/admin/tool/generator/cli/maketestcourse.php
index 940e753b92f..aa57828f5a5 100644
--- a/admin/tool/generator/cli/maketestcourse.php
+++ b/admin/tool/generator/cli/maketestcourse.php
@@ -35,6 +35,7 @@ list($options, $unrecognized) = cli_get_params(
         'shortname' => false,
         'size' => false,
         'fixeddataset' => false,
+        'filesizelimit' => false,
         'bypasscheck' => false,
         'quiet' => false
     ),
@@ -52,11 +53,12 @@ Not for use on live sites; only normally works if debugging is set to DEVELOPER
 level.
 
 Options:
---shortname    Shortname of course to create (required)
---size         Size of course to create XS, S, M, L, XL, or XXL (required)
---fixeddataset Use a fixed data set instead of randomly generated data
---bypasscheck  Bypasses the developer-mode check (be careful!)
---quiet        Do not show any output
+--shortname      Shortname of course to create (required)
+--size           Size of course to create XS, S, M, L, XL, or XXL (required)
+--fixeddataset   Use a fixed data set instead of randomly generated data
+--filesizelimit  Limits the size of the generated files to the specified bytes
+--bypasscheck    Bypasses the developer-mode check (be careful!)
+--quiet          Do not show any output
 
 -h, --help     Print out this help
 
@@ -76,6 +78,7 @@ if (empty($options['bypasscheck']) && !debugging('', DEBUG_DEVELOPER)) {
 $shortname = $options['shortname'];
 $sizename = $options['size'];
 $fixeddataset = $options['fixeddataset'];
+$filesizelimit = $options['filesizelimit'];
 
 // Check size.
 try {
@@ -93,5 +96,5 @@ if ($error = tool_generator_course_backend::check_shortname_available($shortname
 \core\session\manager::set_user(get_admin());
 
 // Do backend code to generate course.
-$backend = new tool_generator_course_backend($shortname, $size, $fixeddataset, empty($options['quiet']));
+$backend = new tool_generator_course_backend($shortname, $size, $fixeddataset, $filesizelimit, empty($options['quiet']));
 $id = $backend->make();
diff --git a/admin/tool/generator/cli/maketestsite.php b/admin/tool/generator/cli/maketestsite.php
index 1e2a7d40141..cd9985c58bc 100644
--- a/admin/tool/generator/cli/maketestsite.php
+++ b/admin/tool/generator/cli/maketestsite.php
@@ -34,6 +34,7 @@ list($options, $unrecognized) = cli_get_params(
         'help' => false,
         'size' => false,
         'fixeddataset' => false,
+        'filesizelimit' => false,
         'bypasscheck' => false,
         'quiet' => false
     ),
@@ -57,10 +58,11 @@ Consider that, depending on the size you select, this CLI tool can really genera
 $sitesizes
 
 Options:
---size         Size of the generated site, this value affects the number of courses and their size. Accepted values: XS, S, M, L, XL, or XXL (required)
---fixeddataset Use a fixed data set instead of randomly generated data
---bypasscheck  Bypasses the developer-mode check (be careful!)
---quiet        Do not show any output
+--size           Size of the generated site, this value affects the number of courses and their size. Accepted values: XS, S, M, L, XL, or XXL (required)
+--fixeddataset   Use a fixed data set instead of randomly generated data
+--filesizelimit  Limits the size of the generated files to the specified bytes
+--bypasscheck    Bypasses the developer-mode check (be careful!)
+--quiet          Do not show any output
 
 -h, --help     Print out this help
 
@@ -79,6 +81,7 @@ if (empty($options['bypasscheck']) && !$CFG->debugdeveloper) {
 // Get options.
 $sizename = $options['size'];
 $fixeddataset = $options['fixeddataset'];
+$filesizelimit = $options['filesizelimit'];
 
 // Check size.
 try {
@@ -91,5 +94,5 @@ try {
 \core\session\manager::set_user(get_admin());
 
 // Do backend code to generate site.
-$backend = new tool_generator_site_backend($size, $options['bypasscheck'], $fixeddataset, empty($options['quiet']));
+$backend = new tool_generator_site_backend($size, $options['bypasscheck'], $fixeddataset, $filesizelimit, empty($options['quiet']));
 $backend->make();
diff --git a/admin/tool/generator/tests/maketestcourse_test.php b/admin/tool/generator/tests/maketestcourse_test.php
index b8637f4eb34..b5afea0bc04 100644
--- a/admin/tool/generator/tests/maketestcourse_test.php
+++ b/admin/tool/generator/tests/maketestcourse_test.php
@@ -35,7 +35,7 @@ class tool_generator_maketestcourse_testcase extends advanced_testcase {
         $this->setAdminUser();
 
         // Create the XS course.
-        $backend = new tool_generator_course_backend('TOOL_MAKELARGECOURSE_XS', 0, false, false);
+        $backend = new tool_generator_course_backend('TOOL_MAKELARGECOURSE_XS', 0, false, false, false);
         $courseid = $backend->make();
 
         // Get course details.
@@ -118,7 +118,7 @@ class tool_generator_maketestcourse_testcase extends advanced_testcase {
         $this->setAdminUser();
 
         // Create the S course (more sections and activities than XS).
-        $backend = new tool_generator_course_backend('TOOL_S_COURSE_1', 1, true, false);
+        $backend = new tool_generator_course_backend('TOOL_S_COURSE_1', 1, true, false, false);
         $courseid = $backend->make();
 
         // Get course details.
@@ -151,4 +151,57 @@ class tool_generator_maketestcourse_testcase extends advanced_testcase {
         }
 
     }
+
+    /**
+     * Creates a small test course specifying a maximum size and checks the generated files size is limited.
+     */
+    public function test_filesize_limit() {
+
+        $this->resetAfterTest();
+        $this->setAdminUser();
+
+        // Limit.
+        $filesizelimit = 100;
+
+        // Create a limited XS course.
+        $backend = new tool_generator_course_backend('TOOL_XS_LIMITED', 0, false, $filesizelimit, false);
+        $courseid = $backend->make();
+
+        $course = get_course($courseid);
+        $modinfo = get_fast_modinfo($course);
+
+        // Check there are small files.
+        $fs = get_file_storage();
+        $resources = $modinfo->get_instances_of('resource');
+        foreach ($resources as $resource) {
+            $resourcecontext = context_module::instance($resource->id);
+            $files = $fs->get_area_files($resourcecontext->id, 'mod_resource', 'content', false, 'filename', false);
+            foreach ($files as $file) {
+                if ($file->get_mimetype() == 'application/octet-stream') {
+                    $this->assertLessThanOrEqual($filesizelimit, $file->get_filesize());
+                }
+            }
+        }
+
+        // Create a non-limited XS course.
+        $backend = new tool_generator_course_backend('TOOL_XS_NOLIMITS', 0, false, false, false);
+        $courseid = $backend->make();
+
+        $course = get_course($courseid);
+        $modinfo = get_fast_modinfo($course);
+
+        // Check there are small files.
+        $fs = get_file_storage();
+        $resources = $modinfo->get_instances_of('resource');
+        foreach ($resources as $resource) {
+            $resourcecontext = context_module::instance($resource->id);
+            $files = $fs->get_area_files($resourcecontext->id, 'mod_resource', 'content', false, 'filename', false);
+            foreach ($files as $file) {
+                if ($file->get_mimetype() == 'application/octet-stream') {
+                    $this->assertGreaterThan($filesizelimit, (int)$file->get_filesize());
+                }
+            }
+        }
+
+    }
 }