[Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?

[Dev Mohanty]

Bryan I assume, this is in reference with the deployment planned at the
new schools, and guess am more then familiar with admin workload and
power limitations you
happen to mention in Nepal.

Hence was wondering if you've looked into the option of using more then one
XS, installed at the same location (eg DOE, OLE) if not at the
schools, this might make it a lot easier to administer. One XS could cater
to students in 3 schools while the other could register students/XOs from
the other two schools, for load balancing.. As am not too sure that using
additional RAM would get the desired results. And
ofcourse there's the 4GB RAM limitations on a 32bit processor, unless you
plan to use a PAE switch and tweak the kernel too and guess
that would be getting into murky waters.

Besides, as Martin pointed out using a 64bit processor would
require the XS iso to be completely
rebuilt, which might take a while forthcoming. Though, I've heard that
AMD's Athlon processors are backward
compatible with 32bit applications and permit use of more then 4GB RAM
without PAE, guess food for thought if you're adamant on using just one XS
for all the schools to reduce the overhead.

But still believe getting ejabberd to
perform with 400 simultaneous users, might still be a tough task.

Cheers,
Dev

On 3/8/09, Bryan Berry <bryan at olenepal.org> wrote:
>
> On Sun, 2009-03-08 at 13:33 +1300, Martin Langhoff wrote:
> > Bryan,
> >
> > I'm on the road, apologies if I'm a bit succint...
> >
> >  - 400 users are unlikely to be online at the same time, supporting
> > all users online at the same time will stress all the infra, so the
> > path to success is, I suspect, paved with strategies to define usage
> > patterns that avoid clustering everyone at the same time.
>
>
> But 200-300 users could be online at once. I think it will be too
> complicated to tell some of them: "Don't connect to the AP right now,
> you may overwhelm ejabberd"
>
>
> >  - I am working on 0.6 which will let you partition the school --
> > instead of @online@, large schools can set moodle+ejabberd in a mode
> > where users are in a shared-roster-group defined by their course
> > membership in moodle. I've posted on the list and written in the wiki
> > about this before if you need more detail.
> >
> >  - More users - more RAM to the server :-) and disk space for backups
>
> we can provide that
>
>
> >  - Do you really have a low latency / high bw conn between the schools
> > and the location with the XS? I have the feeling we had this
> > conversation before... :-) and I suggested smaller and local, which is
> > how the XS is designed to work. That's still my recommendation...
>
>
> The XS is quite a complicated ensemble of software having an XS at every
> school magnifies the administration work. Having a centralized XS for
> several schools can dramatically reduce administrative overhead.
>
> Additionally our schools only have about 8 hours of electricity per day.
> I am concerned about the XS losing power suddenly multiple times per
> day.
>
> We have a relatively low latency connection b/w the schools and the XS.
>
> We have discussed these issues before and I believe that we both came to
> the conclusion that Nepal has different requirements than some of the
> other pilot schools.
>
>
> --
> Bryan W. Berry
> Technology Director
> OLE Nepal, http://www.olenepal.org
>
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>
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>
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