Freezing, Request Timeout - performance problem


 
Thread Tools Search this Thread
Operating Systems Linux Red Hat Freezing, Request Timeout - performance problem
# 1  
Old 02-04-2010
Freezing, Request Timeout - performance problem

Hi,

The server is Redhat 5 32bit.

It is not easy to produce the problem so I will just write the experienced problems not how it is produced.

1) During login, it shows the last login time and then waits for 3-4 seconds to give shell prompt (considerable)
2) Sometimes the connection window freezes (console is also) not showing any characters pressed; after 4-5 seconds it shows all the characters written. (considerable)
3) Almost every half an hour, while pinging the server it shows Request Timeout then the NFS share drops. Smilie
4) CPU is seen as 99 %idle in sar output for the normal times. When the freeze happens the sar output shows 0 %idle, 70 %iowait and 30 %system.
Then the screen freeze and connection drops. Smilie

Any recommendation to check where the problem might be? Any ideas? Smilie
# 2  
Old 02-04-2010
The login delay probably is because of SSH trying to do an reverse lookup. You can disable that by setting
Code:
UseDNS no

in your sshd_config

As for your main problem: if it's occurring periodically, it's probably a cronjob. Check those for anything requiring a lot of memory, as it could be connected to massive swapping.
# 3  
Old 02-05-2010
Thanks pludi,
The line was commented in configuration but I don't know if it is enabled by default. Anyway, after I changed that, it responded normally during login.

For the freezing problem, it doesn't happen periodically. It is hard to generate without knowing where it hangs but the problem seems to be less than before when the update service is stopped.

Edit: After many tries, finally the problem is nfs-related. Whenever a file is imported with script ,which triggers with new added file, the problem occurs. The CPU goes 100% and the timeout messages show up; still the transfer completes.

Last edited by royalliege; 02-05-2010 at 03:20 PM.. Reason: Problem source found
Login or Register to Ask a Question

Previous Thread | Next Thread

8 More Discussions You Might Find Interesting

1. Solaris

I can't copy any file to any machine | abort problem | freezing

I want to copy tar file to another machine. tar size is 4gb. Firstly I tried copy to windows machine with ftp client but copy operation didn't start. Now I have tryied to copy to solaris machine command with scp but copy was freezed. Picture is attached.... (1 Reply)
Discussion started by: getrue
1 Replies

2. UNIX for Dummies Questions & Answers

Implementing TLS with Sendmail and having problem with cert request

Hi. One of my company's customers requires mails to be sent to them to use TLS. Thanks to some good documentation on the web, I've got this mostly figured out, but now I'm stuck at generating the CSR. My company's mail domain is sg.bunny.com (not real address, obviously), but the email gateway... (0 Replies)
Discussion started by: pierreery
0 Replies

3. Shell Programming and Scripting

EXCEPT timeout problem

i am trying to write an except script to ssh into a list of devices and run some commands, and i came across this problem, not every device is alive, which breaks the script, my script looks like this #!/usr/bin/expect # set defaults set... (1 Reply)
Discussion started by: fedora
1 Replies

4. Shell Programming and Scripting

sftp expect timeout problem

hello All, I am doing SFTP using expect. We just change our server from sun solaris 8 to sun solaris 10. The script was working good on sun solaris 8. But it is giving problem on 10. from shell, SFTP is working fine.Please help me. What can be the problem. LIB_sftp_get() { ... (0 Replies)
Discussion started by: mindtee_abhi
0 Replies

5. UNIX for Advanced & Expert Users

timeout opening writing control channel /dev/initctl problem occur i cant shoudown

Hi... This is message that occurs when i am trying to shutdown the linux system timeout opening writing control channel /dev/initctl how can i shutdown what is the problem here.. Thanks in advance ... (2 Replies)
Discussion started by: arunkumar_mca
2 Replies

6. HP-UX

URGENT HELP REQUEST!!!!Connection problem between HP3000 and HP9000

Hi, I am facing some problem in connecting the database(allbase) present on HP3000 through pro c programmin language that is being executed from HP 9000 machine could any one of you please help me!!! when i run the code on HP9000 machine it is connecting to database(access the local host)... (0 Replies)
Discussion started by: ahmedwaseem2000
0 Replies

7. Filesystems, Disks and Memory

timeout problem

Hi can anyone help with the following:- when sending large e-mails via a ssh session the job always times out every 5 min before the mail is sent, this means that a user has to tap a key to stop it timming out. Is there a way to stop this from happening. Numpty (4 Replies)
Discussion started by: numpty
4 Replies

8. UNIX for Advanced & Expert Users

performance problem

Hello, I have a mail server (sendmail) with SUNOS 5.5.1. Just recently it began to respond very slowly. I used vmstat to check the performance data. Only interupt, system call and CPU context swiching are relatively high. Other statistics are normal, especially CPU utilization are very... (5 Replies)
Discussion started by: caoai
5 Replies
Login or Register to Ask a Question