[K12OSN] Poor performance woes

[Gideon Romm]

Try enabling NBD_SWAP.  If the clients have insufficient RAM, the best
you can do is add swap space and hope the OS will swap out something
else.

-Gadi

On Tue, Sep 20, 2011 at 3:18 PM, Jomegat <jomegat at jomegat.com> wrote:
> I have a K12Linux setup based on EL6-64.  The TC's are ancient i686's with
> 256M RAM and 10/100 nics.  The TS has a gigE NIC, and between the TS & TCs
> is a managed switch with 2 gigE ports and 24 10/100 ports.  The TS is
> connected via one of the gigE's.
>
> We have a student who is having real performance problems when he loads a
> page.  I went in today to be there while he was experiencing woe, and ran
> the system monitor applet.
>
> 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.
>
> I had tried running firefox as a local app last month, but the school needs
> flash, and it requires 512M.  Performance on these TC's was substantially
> worse when running FF as a local app, so I backed off of that.
>
> The page he was trying to load is password protected, but I had him ctrl-U
> while he had it open, and save the source to a file which I can share if
> need be.  It is filled with javascript, but I'm not sure that's the culprit
> (though it seems the most likely suspect).  I found no .flv, FLV, .swf, or
> .SWF in the file anywhere.
>
> As an experiment, I connected a monitor, keybd, and mouse directly to the
> server and had him login there.  The page loads just fine that way.  That
> might be a possible solution, but for some reason, the display is incredibly
> blurry.  If I make that permanent, I'd have to run some cable through the
> wall (they're pinched in the door right now, and barely reach).
>
> Before they called me in to look at this, he had been bringing his mom's
> laptop to school so he could do his work (it's an online course).  If it
> crashes while he is taking a quiz, he loses a test attempt or gets a bad
> grade, so this has to be reliable.
>
> His mom is on the school board, and she is pushing the school to abandon
> LTSP in favor of a Windows solution.  They think that if they install some
> flavor of windows on the TC's they will get better performance, but I
> believe they won't, as flash will need 512M no matter the OS.  I think they
> will need all new PC's if they go that route.
>
> I am on the cusp of losing my network to Windows, at which point I will
> resign my post as unpaid volunteer sysadmin, so if I sound a little
> desperate, now you know why.
>
> Any help here would be greatly appreciated.
>
> --
> Jim Thomas            Principal Applications Engineer  Bittware, Inc
> jthomas at bittware.com  http://www.bittware.com    (603) 226-0404 x536
> The problem with the future is that it keeps turning into the present -
> Hobbes
>
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