Linux - Server This forum is for the discussion of Linux Software used in a server related context.
Notices
Welcome to
LinuxQuestions.org , a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free.
Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
Are you new to LinuxQuestions.org? Visit the following links:
Site Howto |
Site FAQ |
Sitemap |
Register Now
If you have any problems with the registration process or your account login, please
contact us . If you need to reset your password,
click here .
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a
virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month.
Click here for more info.
07-11-2009, 01:35 PM
#1
Member
Registered: May 2008
Location: India
Distribution: Ubuntu 10.04, CentOS, Manjaro
Posts: 179
Rep:
system performance
Hi All,
Need help to trouble shoot system performance
2 servers with the same configurations, One server performs very well cpu usage is below 20% but the second server it goes above 100%
Hardware:
IBM x3550, 10GB RAM, 2 Quad Core 2.66, 146 15k SAS HDD.
RAID 0
OS Centos 5.3
APPS JBOSS 4.2.3
iostat
###################
Linux 2.6.18-128.1.10.el5.centos.plus (web3) 07/11/2009
avg-cpu: %user %nice %system %iowait %steal %idle
0.24 0.00 0.01 0.01 0.00 99.73
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 0.37 0.36 9.25 742524 19080318
sda1 0.00 0.00 0.00 2082 46
sda2 0.00 0.00 0.00 1728 0
sda3 0.37 0.36 9.25 738378 19080272
iostat -xd
###########################
Linux 2.6.18-128.1.10.el5.centos.plus (web3) 07/11/2009
Dev: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.80 0.01 0.35 0.36 9.25 26.18 0.01 26.12 4.77 0.18
sda1 0.00 0.00 0.00 0.00 0.00 0.00 17.02 0.00 13.12 8.40 0.00
sda2 0.00 0.00 0.00 0.00 0.00 0.00 36.77 0.00 10.68 9.55 0.00
sda3 0.00 0.80 0.01 0.35 0.36 9.25 26.18 0.01 26.12 4.77 0.18
hdparm -tT /dev/sda
##############################
/dev/sda:
Timing cached reads: 18572 MB in 1.99 seconds = 9310.58 MB/sec
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate ioctl for device
Timing buffered disk reads: 314 MB in 3.02 seconds = 103.86 MB/sec
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate ioctl for device
Mount Points
==============
/dev/sda1 /boot
/dev/sda2 swap
/dev/sda3 /
Can someone explain me how should I consider avgrq-sz, avgqu-sz, await, svctm, %util to calculate the system performance
meaning
await min should be this figure for 15k HDD
svctm should be this much and so on..
I am really confused reading the documentations
Please help
//Remy
07-11-2009, 02:01 PM
#2
Senior Member
Registered: May 2006
Location: USA
Distribution: Debian
Posts: 4,824
That says 0.26% CPU usage. get a snapshot of "w" and "ps -ef" when the system is under load.
07-12-2009, 12:28 AM
#3
Member
Registered: May 2008
Location: India
Distribution: Ubuntu 10.04, CentOS, Manjaro
Posts: 179
Original Poster
Rep:
Quote:
Originally Posted by
AlucardZero
That says 0.26% CPU usage. get a snapshot of "w" and "ps -ef" when the system is under load.
Sure I will capture the output of w and ps -ef and post it.
Mean while
I captured the output of top for the user running JBOSS Apps with a sleep of 5 sec in a while loop
top -b -n 1 <PID_OF_USER_RUNNING_JBOSS> >> /tmp/log.txt &
kept monitoring the file as well as the top command output
tail -f /tmp/log.txt and in another window monitor the output of top
the output of both differ
eg:
Output1
In the log file it shows 102% CPU
top will show 85% CPU
Output2
In the log file it shows 45% CPU
top will show 72% CPU
and so on..
Is it because of the time interval?
Can some one explain me?
//Remy
07-12-2009, 01:34 AM
#4
Senior Member
Registered: Jun 2008
Location: Eelam
Distribution: Redhat, Solaris, Suse
Posts: 1,278
Rep:
yess in default top updating result every 3 seconds so it will result average of 3 seconds values however you can change this time interval
07-12-2009, 03:44 AM
#5
Member
Registered: May 2008
Location: India
Distribution: Ubuntu 10.04, CentOS, Manjaro
Posts: 179
Original Poster
Rep:
Quote:
Originally Posted by
kirukan
yess in default top updating result every 3 seconds so it will result average of 3 seconds values however you can change this time interval
output of w
08:42:01 up 24 days, 11:21, 4 users, load average: 0.84, 1.00, 1.15
"USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT"
"root pts/1 <MY IP> 04:29 11:07 1.39s 0.05s -bash"
"aares00 pts/2 <MY IP> 07:10 1:29m 10.91s 10.90s top"
"root pts/3 <MY IP> 05:29 0.00s 0.03s 0.03s -bash"
output of ps is attached
Last edited by mario.almeida; 07-12-2009 at 02:47 PM .
07-12-2009, 05:57 AM
#6
Senior Member
Registered: Jun 2008
Location: Eelam
Distribution: Redhat, Solaris, Suse
Posts: 1,278
Rep:
wrap CODE or QUOTE, please use these formatting tools to format your outputs
07-12-2009, 08:45 AM
#7
Member
Registered: May 2008
Location: India
Distribution: Ubuntu 10.04, CentOS, Manjaro
Posts: 179
Original Poster
Rep:
Quote:
Originally Posted by
kirukan
wrap CODE or QUOTE, please use these formatting tools to format your outputs
Should I repost?
07-12-2009, 08:47 AM
#8
Senior Member
Registered: May 2006
Location: USA
Distribution: Debian
Posts: 4,824
No, you can edit your post.
Sorry, can you get "ps aux" instead? I'm too used to Unixes where "aux" doesn't work, but that's what we want here.
You have two quad cores, so eight cores. Your load average is only around 1; it's not Bad until you get above 8 (1/core), then you're overloaded.
Last edited by AlucardZero; 07-12-2009 at 08:49 AM .
07-13-2009, 01:44 AM
#9
Member
Registered: May 2008
Location: India
Distribution: Ubuntu 10.04, CentOS, Manjaro
Posts: 179
Original Poster
Rep:
Quote:
Originally Posted by
AlucardZero
No, you can edit your post.
Sorry, can you get "ps aux" instead? I'm too used to Unixes where "aux" doesn't work, but that's what we want here.
You have two quad cores, so eight cores. Your load average is only around 1; it's not Bad until you get above 8 (1/core), then you're overloaded.
Out put of ps aux attached
07-13-2009, 08:14 AM
#10
Senior Member
Registered: May 2006
Location: USA
Distribution: Debian
Posts: 4,824
Well, there's nothing using the CPU in that snapshot, and there are not processess in uninterruptible sleep (state 'D'). I don't see a problem in that snapshot.
All times are GMT -5. The time now is 06:56 PM .
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know .
Latest Threads
LQ News