[Thinlinc-technical] More users / Less servers

[Marcos de Souza Trazzini - Avancera]

Hi there!

Based on some "high-load-related" issues that I sent to the CENDIO AB
Support Tracker, I think it is a good idea to let you know that I´m doing
something to make ThinLinc Linux sessions run faster and also raise the
server´s user density.

Actually, I´ve made some calculations based on user´s memory usage on a real
server (at UERJ) running GNOME 2.26, Firefox 3.0 and OpenOffice 2.4, and
than I  realized that each user consumes from 250 to 350MB of RAM
(consolidating all processes resident set size, RSS), exactly like you
already said some issues ago, but these numbers makes me worried, since the
server´s users density is quite limited this way. For instance, about 12
users for a 4GB server is extremely low, if we consider that we have some
WTS 4GB servers up-and-running with more than 80 users. I don´t want to
reach these "magic numbers" over a Linux server, but it will be nice for all
us to be as nearest as possible.

I could see that GNOME is the great villain here, since it starts a lot of
processes to "build" each user´s desktop, followed by Firefox. Based on
that, I was thinking on some possible solutions:

1) Make GNOME consume less memory: I know this sounds more like "end the
World´s hungry" or "make Windows uncrashable", but I still have some hope. I
tryed to tune-up GNOME using gconf entries, disabling several features that
could drain much memory, and also tryed disabling some DBUS services. The
result was a quite lightweight desktop environment, that I call ThinLinc
Desktop (TLDESKTOP), but some GNOME pieces still seems to devour memory,
like nautilus.


2) Make Firefox consume less memory: Yeah, build a "thin-Firefox" seems to
be a great challenge. I´ve tried two approaches together: (1) tune-up
several about:config entries to disable some features and (2) create a addon
based on R-Kiosk to disable some chrome extensions and also limit user
interativity (like changing options, view page source, print, etc) with the
browser. The result was nice, really better than the "pure" Firefox, but I´m
still not satisfied, and have plans to compile Firefox by myself, disabling
some stuff directly on compilation time and getting smaller binaries as
result.


3) Makes ThinLinc server´s "smarter", to avoid high-memory consumption: The
idea here is simple, I want to avoid creating more sessions than the server
can handle. I had some ideas that I would like to share with you. For
example, perhaps if we, based on the user´s pre-defined memory consumption
(like 250MB per user), define that the server could handle 15 sessions, we
could create a way to count down how many sessions are already opened and
deny opening new sessions according to the pre-defined "max-sessions"
limit... 


Please let me know if any of my ideas makes sense for you, or even if you
are already making efforts on this area acually.

OS: This is not really na issue

Kind regards.

--
Marcos S. Trazzini
ThinLinc Technical Manager
Avancera Brazil IT Services Ltda
Al Caiapós, 465 - Alphaville
Barueri - SP - Brazil
Cel +55 (11) 9941-0773
Tel +55 (11) 3522-8570
marcos.trazzini at avancera.com.br <mailto:marcos.trazzini at avancera.com.br> 
http://www.avancera.com.br/

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