Discussion:
LTSP slowness problem
(too old to reply)
Kenneth Lundström
2015-04-14 10:59:56 UTC
Permalink
Hello everyone,



I have a strange problem that I have been trying to solve for months.



A client have a setup of 6-7 LTSP terminals and one server. Because of room structure we need to have 3 switches, all are 1 GB. Server has one 1GB network card. As I couldn't get LTSP working on CentOS 7 I switched to Ubuntu.



Problem is the slowness of the clients. If 1-2 are working everything is fine, but when we have like 5 working the same time we get slowness, like when writing an email in Thunderbird it just stops showing the writing on the screen.



I swtich away from KDE to LightDM (I think was the name), still same.



One thing we think might be the problem is the filemanager. When somebody open filemanager and looks at the folder with like 100 files everything stop. All files are on the same server as LTSP is running.



Any ideas where to look for the problem and solving it.





Kenneth
Jim Kinney
2015-04-14 11:25:11 UTC
Permalink
Sounds like the server is just too weak for the load. RAM matters. Multiple
hard drives can make a big difference.
1g network for only 7 clients is plenty unless its all youtube videos.
Post by Kenneth Lundström
Hello everyone,
I have a strange problem that I have been trying to solve for months.
A client have a setup of 6-7 LTSP terminals and one server. Because of
room structure we need to have 3 switches, all are 1 GB. Server has one 1GB
network card. As I couldn't get LTSP working on CentOS 7 I switched to
Ubuntu.
Problem is the slowness of the clients. If 1-2 are working everything is
fine, but when we have like 5 working the same time we get slowness, like
when writing an email in Thunderbird it just stops showing the writing on
the screen.
I swtich away from KDE to LightDM (I think was the name), still same.
One thing we think might be the problem is the filemanager. When somebody
open filemanager and looks at the folder with like 100 files everything
stop. All files are on the same server as LTSP is running.
Any ideas where to look for the problem and solving it.
Kenneth
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For more info see <http://www.k12os.org>
Burke Almquist
2015-04-16 01:57:46 UTC
Permalink
Post by Kenneth Lundström
Hello everyone,
I have a strange problem that I have been trying to solve for months.
A client have a setup of 6-7 LTSP terminals and one server. Because of room structure we need to have 3 switches, all are 1 GB. Server has one 1GB network card. As I couldn't get LTSP working on CentOS 7 I switched to Ubuntu.
Problem is the slowness of the clients. If 1-2 are working everything is fine, but when we have like 5 working the same time we get slowness, like when writing an email in Thunderbird it just stops showing the writing on the screen.
I swtich away from KDE to LightDM (I think was the name), still same.
One thing we think might be the problem is the filemanager. When somebody open filemanager and looks at the folder with like 100 files everything stop. All files are on the same server as LTSP is running.
Any ideas where to look for the problem and solving it.
Kenneth
How much memory does your server have?

Jim Kinney
2015-04-14 12:15:34 UTC
Permalink
That python process is eating the system.
Need cpuinfo as well. How many cores? A single core can get bogged down
swapping memory out between user jobs and system jobs.

Note: Intel cpus use their hyperthreading mode. That's only useful for
processes that are shared memory. When the use is non-shared memory work,
hyperthreading can actually slow down the system. I turn it off by default
in the bios.
Hi,
top - 14:29:39 up 11 days, 5:43, 6 users, load average: 1,98, 2,16, 2,03
Tasks: 402 total, 3 running, 397 sleeping, 1 stopped, 1 zombie
%Cpu(s): 12,4 us, 3,8 sy, 0,0 ni, 81,7 id, 2,0 wa, 0,0 hi, 0,1 si,
0,0 st
KiB Mem: 16593728 total, 9841308 used, 6752420 free, 291936 buffers
KiB Swap: 16773116 total, 0 used, 16773116 free. 6716260 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
11101 xx1 20 0 110524 34928 21764 R 100,0 0,2 10231:46 python
18506 xx1 20 0 1000664 278496 45620 S 16,9 1,7 13:57.25 firefox
32129 xx2 20 0 784320 274336 44752 S 3,0 1,7 12:11.78
thunderbird
32133 xx2 20 0 1058788 352892 46728 R 2,7 2,1 13:16.16 firefox
31698 root 20 0 10144 3268 2508 S 1,7 0,0 0:00.11 sshd
23 root 20 0 0 0 0 S 0,7 0,0 8:25.98
ksoftirqd/3
16121 root 20 0 0 0 0 S 0,7 0,0 0:05.42
kworker/1:2
18 root 20 0 0 0 0 S 0,3 0,0 10:11.20
ksoftirqd/2
38 root 20 0 0 0 0 S 0,3 0,0 9:52.39
ksoftirqd/6
43 root 20 0 0 0 0 S 0,3 0,0 8:30.15
ksoftirqd/7
1776 xx3 20 0 335288 41872 19920 S 0,3 0,3 0:50.63
plugin-containe
16798 xx4 20 0 874020 292644 45340 S 0,3 1,8 1:27.02 firefox
19382 xx4 20 0 233152 26560 16572 S 0,3 0,2 0:07.70
plugin-containe
30002 xx2 20 0 231240 27512 17564 S 0,3 0,2 0:01.89
plugin-containe
If I remember correctly it is running on two harddisk but in mirror mode.
Kenneth
-----Original message-----
*Sent:* Tuesday 14th April 2015 14:27
*Subject:* Re: [K12OSN] LTSP slowness problem
Sounds like the server is just too weak for the load. RAM matters.
Multiple hard drives can make a big difference.
1g network for only 7 clients is plenty unless its all youtube videos.
Post by Kenneth Lundström
Hello everyone,
I have a strange problem that I have been trying to solve for months.
A client have a setup of 6-7 LTSP terminals and one server. Because of
room structure we need to have 3 switches, all are 1 GB. Server has one 1GB
network card. As I couldn't get LTSP working on CentOS 7 I switched to
Ubuntu.
Problem is the slowness of the clients. If 1-2 are working everything is
fine, but when we have like 5 working the same time we get slowness, like
when writing an email in Thunderbird it just stops showing the writing on
the screen.
I swtich away from KDE to LightDM (I think was the name), still same.
One thing we think might be the problem is the filemanager. When somebody
open filemanager and looks at the folder with like 100 files everything
stop. All files are on the same server as LTSP is running.
Any ideas where to look for the problem and solving it.
Kenneth
_______________________________________________
K12OSN mailing list
https://www.redhat.com/mailman/listinfo/k12osn
For more info see <http://www.k12os.org>
_______________________________________________
K12OSN mailing list
https://www.redhat.com/mailman/listinfo/k12osn
For more info see <http://www.k12os.org>
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