[K12OSN] More feedback on Fedora 10 + LTSP

Tue Apr 21 21:50:21 UTC 2009

I know you're at your wits' end here, and so is that teacher.  This is 
not good.

Remind us what sound card is in these thin clients, would you?

--TP
_______________________________
Do you GNU <http://www.gnu.org>?
Microsoft Free since 2003 <http://www.cmosnetworks.com>--the ultimate 
antivirus protection!

David Hopkins wrote:
> Let me first say that this is going to sound like a rant in places.
> Not much I can do about that, but ... FC10+LTSP5 has not been
> performing well at all.  I am currently at a loss to explain why.
> However, since I have to have sound working, LTSP5 seems to be the
> only way to ensure that sound works correctly. I have CentOS+LTSP4.2
> and that works well for everything except sound. So, the only option I
> see is to get a distribution that is using LTSP5 working. Again, just
> to be clear, I am using identical hardware for the comparison and
> using the same login accounts, same file server, same dns, same
> authentication server, etc. All hardware is 32bit, both server and
> clients. (I don't even want to deal/worry with the 64bit server/32bit
> client possible issues at the moment).
>
> Now, here is what I and the elementary school tech teacher observed
> today. The following is her write-up.
>
> "Things did not go so well this morning.  When all 10 computers were
> in use at the same time, the delay between mouse and screen was
> significant. . .  The point of the lesson was to improve mouse
> skills--not possible when there is a lag between their mouse movements
> and action on their monitors.   We muddled through the first group of
> 10 students, and when the 2nd group began the exercise, I allowed the
> first 10 students to open Tux Paint.  I thought because  Tux Paint is
> running local, this would work.  Big Mistake!  The delay for everyone
> increased dramatically, making it virtually impossible to complete the
> mouse task in Starfall.   When I tried to "QUIT" foxfire on 3
> computers, it took 3-4 minutes to return to the desktop.   Although I
> was circulating the room, trying to assist students, I glanced at the
> load several times--I never saw it rise above 6.  It mostly hovered
> between 4 and 5.  It took more than 5 minutes to successfully close
> the website from 10 computers.  During that time, I had 10 students
> just waiting.
>
> When my second class arrived, I did not even try to use the website.
> We used Tux Paint today.  However, shortly after we got started, I
> "banned" students from selecting a new piece of paper . . .  The few
> who had tried feature  had their monitor hung-up for more than a
> minute.  That task used to respond immediately.   There is also a
> terrific feature that allows students to select any color from the
> rainbow . . .  but choosing that feature takes more than 1 full minute
> to accomplish."
>
> This is on a system where with CentOS+LTSP4.2 I could run 25 systems
> simultaneously without issues.  She was trying to use 10.
>
> Notice that the load average never exceeded 6. This is dual
> hyperthreaded Xeon so a load average of 4 would mean 100% utilization
> although that is a bit misleading as load averages of 6-8 perform
> quite well on all my other systems. Also, the system was never using
> swap. In fact, memory usage never exceeded 5GB.
>
> So, where is the bottleneck?  The starfall activity is flash-based (it
> was the Earth Day activity).  I know that FF3+flash is going to load
> the system.  But, This issue is not as severe with FF2+Flash 9 except
> that you don't get sound half the time.  FF3+Flash10 seems to really
> slow down.  Also, it seems that network traffic is significantly
> higher with FC10+LTSP5 using ldm than with gdm.  Can I switch back to
> gdm as the default manager or is ldm it?  I have the LDM_DIRECTX set
> to TRUE so that ssh is only used for login/logout.  And, login/logout
> now takes 30+ secs compared to about 2 seconds for CentOS+LTSP4.2.
>
> For the local apps, launching FF3 can take over a minute. And then it
> will be sluggish, even when the local hardware isn't using swap
> either.
>
> I have this suspicion that it is a network bandwidth issue. The only
> difference there is that LTSP5 uses the ltsbr0 bridge setup while
> LTSP4.2 does not.  To test this, I should be able to delete the bridge
> and set up LTSP5 in the same dual NIC scenario as with LTSP4.2,
> correct?  Though I am not sure I have the skills to do so without
> breaking something else.  It might be as easy as deleting the ltsbr0
> entry and then defining the IP address for the currently-slaved NIC to
> be what the ltsbr0 was defined as.
>
> I haven't had a chance to look at the stats from the switch (Amer.com,
> SS2R24G4i ) but since I never changed the switch, only the OS, I don't
> see why there would suddenly be an issue.
>
> As for the Tuxpaint issue.  That is truly baffling.  I have the same
> version of Tuxpaint running on an older server and it is very
> responsive. There is a hardware difference for the server ... the one
> that runs very well has CPU's with only 70% the speed of the newer
> server.  The other difference is again CentOS+LTSP4.2 (using gdm) vs
> FC10+LTSP5 (and ldm).
>
> So, something looks like it 'just isn't right' except I'm not getting
> any disk I/O errors, I'm not getting a huge spike in the load ... the
> system just isn't responsive.
>
> At this point the teacher has really reached her limit as have I.  A
> single login with a single client works fine.  Add a few more and I
> get the above. I want LTSP5 to work but I can't stay with it given the
> current performance issues.  And I have to start planning now for next
> fall.  If upgrading to FC10+LTSP5 means all my current hardware is not
> acceptable, then I have a huge issue.  I know that all my current
> hardware works with FC10+LTSP5, but the performance I'm seeing is
> horrible.  I have been advocating/using K12LTSP since 2003, I really
> want this to work, but right now to say I am depressed with FC10+LTSP5
> would be an understatement.
>
> So ... help?  I'll be back at the school tonight to try and determine
> what might be happening. And once there, sitting behind the state
> firewalls, access to IRC is blocked as is all other chat capabilities.
>
> Sincerely,
> Dave Hopkins
> Newark Charter School
>
> _______________________________________________
> K12OSN mailing list
> K12OSN at redhat.com
> https://www.redhat.com/mailman/listinfo/k12osn
> For more info see <http://www.k12os.org>
>   
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/k12osn/attachments/20090421/74c361bd/attachment.htm>