[Server-devel] Latest on capacity of the school server

[David Leeming]

OK good advice thanks.

Power and available operating environment are an issue in the PNG schools.
High temp and humidity and need to run on solar power, but not make it so
expensive it can't be replicated in many schools. We will see how the small
"eboxes" cope and add RAM, and yes we will get you that data when one of the
team can get there. We're working on local tech skills. 

David Leeming

-----Original Message-----
From: Martin Langhoff [mailto:martin.langhoff at gmail.com] 
Sent: Wednesday, 7 July 2010 3:22 a.m.
To: David Leeming
Cc: XS Devel
Subject: Re: [Server-devel] Latest on capacity of the school server

On Thu, Jul 1, 2010 at 1:45 PM, David Leeming
<david at leeming-consulting.com> wrote:
> What experience do we have on the latest thinking about the capacity of a
> single server? Here in Kosrae they have good 24/7 power availability and
> air-conditioned offices in five of the schools. We can therefore specify
> powerful machines, even dedicated server models if need be.  If we
segregate
> off each of the 24 class groups, would a single powerful machine server be
> able to handle 500 students in 24 classes (courses) simultaneously? (of
> course in practice that maximum load will rarely occur).

The XS will be ok. Add RAM (webapps and proxy are memory-bound) and a large
HD.

What *will* melt with 500 active users is the WiFi infra.

> floors, 12 classrooms per floor, in U-shape layout. I would place one AP
per
> classroom spread evenly around the school – that would be about 20
students
> per AP. The APs set up all on eth1 LAN with the same SSID. If we use
> multiple servers, we’d use different SSIDs for each. I have not deployed
> such a large site before so any comments on this would be appreciated.

One AP per 20 is more than good. We've seen some good APs handle 40~50
(with modest traffic).

Do NOT go for multiple servers. Therein lies madness.

> In PNG SDP’s project in North Fly, PNG, we are using small “eboxes”
because
> of the need to run on solar power. We have deployed one full-campus
> wireless/server installation, quite a small school (160 total, 80 users in
> the first roll out). These users are divided into 3 class groups, as
Moodle
> courses. So they are segregated. We have had feedback that it still gets
> slow / congested when all users are on simultaneously (80 users in 3
> separate courses).

Interesting. Ask them for a day and time when it was sliggush within
the last couple of weeks. sysstat is running on the XS. Look at the
/var/log/sa/sar* files (or  call the 'sar' command for today's output)
... It keeps approx 1 month IIRC. Filenames end with the
'day-of-the-month' number.

> I don’t have an opportunity to visit the school and

Damn - anyone with the skills to find those files for you?

cheers,


m
-- 
 martin.langhoff at gmail.com
 martin at laptop.org -- School Server Architect
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