[Server-devel] notes on scaling ejabberd for the XO's

[Bryan Berry]

Here are some notes from a short IRC conversation I had w/ Rob Mcqueen,
the lead developer of Telepathy

transcript of conversation on #sugar
bemasc: bernie: I am concerned about the fact that in the default
schoolserver set up all users are in one giant shared roster
<Robot101> RESOLVED, ALREADYFIXED (but not in any deployments, or in the
UI)
<BryanWB> and the resulting chatter slows down the XO/Sugar
considerably?
<Robot101> yes
 Robot101 rwh
 the latest versions of sugar and telepathy support using an XMPP
component called gadget
 instead of the shared roster
<BryanWB> Robot101: so gadget fixes this?
<Robot101> yup
 Robot101 rwh
 you only receive push notifications about a) what Sugar has searched
for/displaying on the neighborhood view, or b) your friends
--> hgcphoenix (n=hchua at 124.107.253.193) has joined #sugar
<BryanWB> Robot101: neat, and does it work together w/ the XS? 
 Robot101: which version of sugar is it in?
<-- hgcphoenix (n=hchua at 124.107.253.193) has left #sugar
<Robot101> they went off on a complete tangent trying to hack shared
rosters to have less mutually visible sets of people
 we thought of that but also decided it was the bong, so we fixed it
properly with gadget.
<BryanWB> Robot101: what is the testing status of gadget?
<Robot101> it's deployed on jabber.sugarlabs.org (which is on
collabora.co.uk)
 seems to work fine, ejabberd seems to gradually leak memory though,
which isn't too great
 maybe a little much CPU usage on gadget, but nothing you couldn't
profile
 and I'm not familiar enough with the sugar release cycle to say where
the support went in
 Robot101 rwh
 eu daytime is better to find the Sugar devs and the Collaborans who
worked on Gadget
 (cassidy, daf)
<BryanWB> Robot101: ok, will talk w/ them later today
<Robot101> gadget was always our plan, it just took us a while to get to
it
<BryanWB> Robot101: by the way last year we tested ejabberd by streaming
your video talk on Telepathy to 80 XO's
<bemasc> Robot101: I believe martin dropped the shared roster, and
inside is simply using moodle to set all rosters directly.
 s/inside/instead/
 bemasc bernie benzea
<Robot101> bemasc: so it's still shared as in server-enforced mutual
visibility, just in smaller groups.
<bemasc> right, but from ejabberd's perspective, it's individual rosters
<Robot101> that's exactly how shared rosters always work
<Robot101> the client thread gets a copy of the same roster at sign in
<bemasc> oh? I thought there was a patch to ejabberd required.
<Robot101> yes, he's patched it to source the shared roster from moodle,
I'd imagine
<bemasc> martin seemed to say that he could use a totally stock ejabberd
<Robot101> oh, right. sql query or something. our patches were just
extending the built-in shared roster to a) work properly (deal with
dynamic additions and removals) and b) support a group of online users
rather than everyone


-- 
Bryan W. Berry
Technology Director
OLE Nepal, http://www.olenepal.org