[Server-devel] Public folders in 0.6 - trials in Pacific

Martin Langhoff martin.langhoff at gmail.com
Tue Dec 15 06:06:11 EST 2009

Hi David,

sorry about the delay. Great to hear 0.6 installed alright -- I assume
you got your XOs registered and auto-authenticating with Moodle...

On Sat, Dec 12, 2009 at 7:29 AM, David Leeming
<david at leeming-consulting.com> wrote:
> All seems to be working OK. I am going to try setting up groups of users
> (classes) and see how that pans out. Is there any data and guidelines on how
> far a single server can be stretched (number of users etc) ?

 - How powerful is the XS? -- amount of RAM, type, number and speed of
disks and CPU (in that order) affect the peak capacity it can sustain

-  How good is the network coverage? You are _very_ likely to saturate
a single AP with 20 XOs (between http traffic for moodle and other
network traffic such as presence) before you max the server.

- What will they use in Moodle? And how simultaneously? Hint: Quiz is
one of the heaviest modules, if you get a group of users and say
"press 'start this quiz' on the count of 3" you're inciting murder of
your server because the spike of a bunch of users hitting it at
exactly the same time is hard to deal with.

Try with "the quiz is timed, so read the intro paragraph and click on
'start' after you read it". That trick spreads the traffic that was
going to hit in 1s into maybe a minute or two, given the variation on
reading speeds of different people. Congrats -- your server now
handles 60x more traffic.

> I am sorry if this is covered in the list but can you confirm if there is
> any way to upload files to the server from an XO using moodle?

Yes - use the "course files" area for files related to a course
content. You have 'site files' too for stuff available to all. And
many modules allow file uploads (forum, assignment...).

> Last question, it will happen that user groups and all their data will need
> to be migrated. Also backing up user data and then reloading that on a
> freshly configured server. What is the line on that?

If the 'migration' is to a replacement machine that will serve the
same users, easiest path is to clone the disk (for example with
rsync). Or just move the disk to a new machine.

The other option is to use the backup/restore tools for that too.
Daniel Drake wrote them, and "documented" their use in some messages
to this list (great if someone grabs his notes and sticks them in the
wiki ;-) ).

OTOH, if migration means that servers are going to be consolidated or
split, then it is a bitharder.

 martin.langhoff at gmail.com
 martin at laptop.org -- School Server Architect
 - ask interesting questions
 - don't get distracted with shiny stuff  - working code first
 - http://wiki.laptop.org/go/User:Martinlanghoff

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