[K12OSN] Poor performance woes
jomegat at jomegat.com
Tue Sep 20 20:51:18 UTC 2011
On 09/20/2011 04:36 PM, Gideon Romm wrote:
> 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
Thanks. I've already got that enabled as best I can tell. Here's a
snippet from chkconfig --list:
xinetd based services:
Maybe that's where the 21MiB/sec is coming from.
As soon as I can get back to the school, I'll run top on the TC and see
what's going on.
Would it be possible (or advisable) to run swap on the TC from a local
HD instead of over the network?
> 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
>> (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 -
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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 -
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