[K12OSN] Poor performance woes

Jeff Siddall news at siddall.name
Tue Sep 20 22:13:57 UTC 2011

On 09/20/2011 03:18 PM, Jomegat wrote:
> When he loads the web page - with no flash in it that I can find - the
> network maxes out at 12MiB/sec, and it takes an eternity for the page to
> load. He reports that sometimes this particular page will cause the TC
> to crash (black screen with text followed by login screen), but he was
> not able to reproduce that while I was there. I suspect there is some
> user error involved in the crash scenario, but it will be difficult to
> prove.

Unfortunately there are some cases where LTSP just doesn't work well. 
Sounds like you hit one of those where javascript is doing something 
silly with the display and sending raw display updates across the LAN is 
killing things.

You can probably get around the problem of that one page by running the 
browser as a localapp, but of course then there is no flash for that user.

That being said, there are a few things you can do:

1. Try a different browser (ex: chrome).  It may work better and it 
would allow you to run a dual browser (ex: firefox as a localapp and 
chrome as a native).  If the users will put up with it tell them to run 
flash sites in Chrome and all others in Firefox.  Ugly for sure but may 
work for the few exception cases you are running into.

2. Fire up one of those clients as a Windoze machine and load a flash 
page to show that Windows on your clients is a non-option.

3. Try installing more RAM in one client and see if it works any better 
on the problem page.  That should confirm/deny the running out of RAM 
question.  Also, that will allow you to try installing flash in the 
chroot and see if the performance is acceptable.  Maybe you can add some 
RAM to your clients and successfully run them all with localapp browsers.

4. If they are going to upgrade the PCs anyway, try to convince them to 
order them diskless initially and run either LTSP with localapps or 
something like DRBL.  If nothing else they save admin time/effort vs. 
any Windows option plus the cost of all the hard drives and Windoze 
licenses in the clients.  They can still add drives and Windoze after if 
it doesn't work.

Good luck!


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