How do I find the cause for a huge difference in performance between two identical Ubuntu servers?

Posted by the.duckman on Server Fault See other posts from Server Fault or by the.duckman
Published on 2012-12-04T16:57:11Z Indexed on 2012/12/04 17:08 UTC
Read the original article Hit count: 232

Filed under:

linux

|

ubuntu

|

Performance

|

java

|

ubuntu-10.04

I am running two Dell R410 servers in the same rack of a data center. Both have the same hardware configuration, run Ubuntu 10.4, have the same packages installed and run the same Java web servers. No other load.

One of them is 20-30% faster than the other, very consistently. I used dstat to figure out, if there are more context switches, IO, swapping or anything, but I see no reason for the difference. With the same workload, (no swapping, virtually no IO), the cpu usage and load is higher on one server.

So the difference appears to be mainly CPU bound, but while a simple cpu benchmark using sysbench (with all other load turned off) did yield a difference, it was only 6%. So maybe it is not only CPU but also memory performance.

I tried to figure out if the BIOS settings differ in some parameter, did a dump using dmidecode, but that yielded no difference.

I compared /proc/cpuinfo, no difference. I compared the output of cpufreq-info, no difference.

I am lost. What can I do, to figure out, what is going on?

© Server Fault or respective owner

Related posts about linux

apt-get install and update fail

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've got a problem with apt-get update and apt-get install ... commands . every time update or installing fails and errors are : Get:1 http://dl.google.com stable Release.gpg [198B] Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US Get:2 http://dl… >>> More
kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
Build-Essentials installation failing

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo]… >>> More
Updating Debian kernel

as seen on Super User - Search for 'Super User'
I'm trying to update my Debian machine to 2.6.32-46 (which is the new stable). However, after doing apt-get update my apt-cache search linux-image shows me: linux-headers-2.6.32-5-486 - Header files for Linux 2.6.32-5-486 linux-headers-2.6.32-5-686-bigmem - Header files for Linux 2.6.32-5-686-bigmem linux-headers-2… >>> More
Serial connection over a single USB cable (Windows to linux, or linux to linux)

as seen on Server Fault - Search for 'Server Fault'
I'm helping out with a project for an embedded device that only has USB and no serial. This device is running Linux. These days, when we need to connect to a serial port on a device we typically use a USB to serial adapter (on something like a phone system or a load balancing device, etc). I would… >>> More

Related posts about ubuntu

Cannot update, apt-get cannot fetch index files

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have a fresh install of Ubuntu 11.10 from the iso 'ubuntu-11.10-desktop-amd64.iso'. I installed this in VMWare Fusion 4.1.1 running on OSX 10.7.3. When setting up the VM, I allowed easy install to take care of creating my user and installing VMWare tools. No problems during installation, everything… >>> More
'sudo apt-get update' error on Ubuntu 12.04

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
When I type in 'sudo apt-get update' I get this mohd-arafat-hossain@TUD:~$ sudo apt-get update [sudo] password for mohd-arafat-hossain: Ign http://bd.archive.ubuntu.com precise InRelease Ign http://bd.archive.ubuntu.com precise-updates InRelease Ign http://bd.archive.ubuntu… >>> More
Opening Skype, Opera, OpenOffice logs me off

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
Whats common among Skype, Opera, OpenOffice in Ubuntu ? Whenever I open these applications I get logged off and shows back me the login screen. This started happening since the 10.10 upgrade. Forgot to mention : Yes, its x64.Each time I open these applications, the UI shows and then crashes. I… >>> More
Update information outdated

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have a warning triangle that my update information is outdated, the last update was 12 days ago. I use Ubuntu 11.10. A run of sudo apt-get update produces the following output: Ign http://ppa.launchpad.net oneiric InRelease Ign http://de.archive.ubuntu.com oneiric InRelease … >>> More
ubuntu/apt-get update said "Failed to Fetch http:// .... 404 not found"

as seen on Server Fault - Search for 'Server Fault'
Hi all, I'm trying to run apt-get update on ubuntu 9.10 I've configured my proxy server and I can access the internet without any problem: /etc/apt# wget "http://www.google.com" Resolving (...) Proxy request sent, awaiting response... 200 OK Length: 292 [text/html] Saving to: `index.html' 100%[=================================================================================================================================>]… >>> More