nohup has a terrible bad performance compared with interactive command, why?

Login or Register to Ask a Question and Join Our Community

nohup has a terrible bad performance compared with interactive command, why?

Tags

beginners, unresolved, unresolved for weeks

Top Forums UNIX for Dummies Questions & Answers nohup has a terrible bad performance compared with interactive command, why?

02-20-2009

Registered User

1, 0

Join Date: Feb 2009

Last Activity: 20 February 2009, 12:20 AM EST

Posts: 1

Thanks Given: 0

Thanked 0 Times in 0 Posts

nohup has a terrible bad performance compared with interactive command, why?

I have a strange situation. I'm running a shell script containing several data uploads (using Oracle sqlloader utility). This script is being run on a Red Hat server.

I tried to run it in background:

$ nohup upload.sh &

This script uploads some thousands files. After several hours I checked what the nohup.out was showing and I was quite surprised to see it was very and extremely slow, because it just processed around less than a hundred files. Probably it would took more than 3 days to complete...

I ran the script interactively, I mean direct from command line showing output to screen. Surprise! the script ran several times better that when using nohup, finishing less than an hour.

I suspicted this was because the process using nohup has a slower priority than the one being run interactively. That was not true, both processes had the same priority.

Why this behaviour? I'm not a linux expert. Please help.

Thanks

viniciov

View Public Profile for viniciov

Find all posts by viniciov

Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. AIX

AIX lpar bad disk I/O performance - 4k per IO limitation ?

Hi Guys, I have fresh new installed VIO 2.2.3.70 on a p710, 3 physical SAS disks, rootvg on hdisk0 and 3 VIO clients through vscsi, AIX7.1tl4 AIX6.1tl9 RHEL6.5ppc, each lpar has its rootvg installed on a LV on datavg (hdisk2) mapped to vhost0,1,2 There is no vg on hdisk1, I use it for my...

2. Solaris

Performance (iops) becomes bad, what is the reason?

I have written a virtual HBA driver named "xmp_vhba". A scsi disk is attached on it. as shown below: xmp_vhba, instance #0 disk, instance #11 But the performance became very bad when we read/write the scsi disk using the vdbench(a read/write io tool). What is the reason? ...

3. Solaris

Terrible SMB performance!?

Hi, I tried this question on OTN Discussion Forum, but it seems that forum doesn't have as much activity so I thought I'd try here. I have a big performance problem with Samba server on a fresh install of Solaris Express 11 svn_151a, and a freshly created ZFS pool. I'm getting about 3 to 10 MB/s...

4. AIX

Non interactive command output using script command ?

Hello, Script command helps to save command output to file. (Redicection doesn't work in this case). Besides interactive shell 'recording', Linux script command has "-c" option which allows to record output of some non-interactive command. The problem is that AIX script command variant...

5. AIX

Nohup command

I'm trying to run a compress script in the background, but I even though the script is running in the background I get "Sending nohup output to nohup.out." and the screen just stays there. How can I make the script run in background and make my command prompt come back. I was using: nohup...

6. HP-UX

Bad performance but Low CPU loading?

There might be some problem with my server, because every morning at 7, it's performance become bad with no DB extra deadlock. But I just couldn't figure it out. Please give me some advise, thanks a lot... According to the CPU performace chart, Daily CPU loading Maximum: 42 %, Average:36%. ...

7. UNIX for Dummies Questions & Answers

nohup command..

Hi.. Can anybody tell me, what exactly the nohup command does & when is it used? Your help is appreciated.

8. AIX

Bad performance when log in with putty

Hello guys! I'm n00b in AIX and I'm sticked in a problem. (my English is poor enough, but I hope you can understand me :P). So.. I'm trying to connect to an AIX machine with putty, and .. 'using username xxx' appears after 2 sec (OK), but 'xxx@ip's password' appears after 1:15 min. After...

9. UNIX for Dummies Questions & Answers

comparing Huge Files - Performance is very bad

Hi All, Can you please help me in resolving the following problem? My requirement is like this: 1) I have two files YESTERDAY_FILE and TODAY_FILE. Each one is having nearly two million data. 2) I need to check each record of TODAY_FILE in YESTERDAY_FILE. If exists we can skip that by...

10. UNIX for Dummies Questions & Answers

Nohup Command

Hello All, I am newbie to unix.I am trying to use NOHUP command in shell script it works fine with only "nohup test.sh 10 &" and "/opt/user/nohup test.sh 10 &" gives an error saying "ksh: /opt/user/nohup : not found". Can anybody please guide me to make it work. Thanks Blazix

Login or Register to Ask a Question

LEARN ABOUT OPENDARWIN

nohup

NOHUP(1)						    BSD General Commands Manual 						  NOHUP(1)

NAME

     nohup -- invoke a utility immune to hangups

SYNOPSIS

     nohup [--] utility [arguments]

DESCRIPTION

     The nohup utility invokes utility with its arguments and at this time sets the signal SIGHUP to be ignored.  If the standard output is a ter-
     minal, the standard output is appended to the file nohup.out in the current directory.  If standard error is a terminal, it is directed to
     the same place as the standard output.

     Some shells may provide a builtin nohup command which is similar or identical to this utility.  Consult the builtin(1) manual page.

ENVIRONMENT

     The following variables are utilized by nohup:

     HOME  If the output file nohup.out cannot be created in the current directory, the nohup utility uses the directory named by HOME to create
	   the file.

     PATH  Used to locate the requested utility if the name contains no '/' characters.

DIAGNOSTICS

     The nohup utility exits with one of the following values:

     126     The utility was found, but could not be invoked.

     127     The utility could not be found or an error occurred in nohup.

     Otherwise, the exit status of nohup will be that of utility.

SEE ALSO

     builtin(1), csh(1), signal(3)

STANDARDS

     The nohup utility is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.

BUGS

     Two or more instances of nohup can append to the same file, which makes for a confusing output.

BSD
								   July 19, 2001							       BSD