update scale section

Author: bnmnetp

pretext/introduction.ptx

@@ -87,10 +87,18 @@ One of the strengths of Runestone is that many of our features have been created
 <title>A Word about Scale</title>
 <p>This section added in September 2023.</p>
 <p>As you will see in our history, Runestone came out of a small liberal arts college.  Class sizes were around 30 students.  A huge number of our courses are high school AP CS courses using the CSAwesome book.  Those courses tend to be in the 10 -- 60 student range.  For courses that size Runestone has worked well for many years.</p>
-<p>Recently Runestone Academy has become a tool for courses at much larger institutions and consequently we are seeing course sizes grew.  I was totally taken off guard in August of 2023 when three courses containing 1000+ students were created.  To this I would say the following:
+
+<p>
+    Recently Runestone Academy has become a tool for courses at much larger institutions and consequently we are seeing course sizes grew.  I was totally taken off guard in August of 2023 when three courses containing 1000+ students were created.
+</p>
+<p>
+    We have architected the website to be horizontally scalable.  Which means we can support many thousands of courses at the same time.  So, we can support many thousands of courses, but not many thousands of students in a single course.  We are working on that, but it is a big job.  The good news is that the parts that suffer are the parts for the instructor interface.  The student experience is not affected.  So, if you are teaching a course of 1000+ students, your students will not notice any problems.  But you will.  Further good news, the instructor interface is undergoing a major rewrite, so know that we are working on it, and are now aware that 1000+ student courses are a thing.
+</p>
+<p>
+    If you are teaching a course of 500+ students here are some things to keep in mind:
 <ul>
 <li>
-        A 500+ student course has never been a design point for Runestone.  So, yes, things like the gradebook or student progress tabs, are likely to time out.  The good news is that your students will not notice, it just makes your life difficult! Sorry!  We will work on it.  But also recognize that a course of 1000+ puts a lot of additional demand on our servers.
+        Things like the gradebook or student progress tabs, are likely to time out (502 Gateway timeout). The grader itself is probably something you should start when you can just let it run for an hour or more. 
 </li>
 <li>
         If you want to use the practice tool for a very large course then you should definitely set the option to have flashcards generated when a student starts a page or the option for when they complete a page.  If you try to have it generate flashcards for the students when you mark a section as complete you are going to be frustrated!
@@ -99,7 +107,7 @@ One of the strengths of Runestone is that many of our features have been created
         You may also wish to consider breaking a very large course into multiple courses corresponding to different sections.  You can set up one section as a master and then your TAs can copy assignments from the master course.
 </li>
 <li>
-        If you are from an institution that has classes of 1000+ then I would ask that you really make an effort to support Runestone Academy.   Either directly from your department, or stating on your syllabus that students should donate.  In the future we may have to institute a small fee for very large courses.
+        If you are from an institution that has classes of 1000+ then I would ask that you really make an effort to support Runestone Academy.   Either directly from your department, or stating on your syllabus that students should donate. Please recognize that a course of 1000+ puts a lot of additional demand on our servers. We strive to give you a great experience so as more students register we add more servers.  Every server we add costs money. In the future we may be forced to institute a small fee for very large courses just to help us cover our costs.
 </li>
 </ul>