hi,
i want to know cpu utilizatiion per process per cpu..for single processor also if multicore in linux ..to use these values in shell script to kill processes exceeding cpu utilization.ps (pcpu) command does not give exact values..top does not give persistant values..psstat,vmstat..does njot... (3 Replies)
Hello Friends,
On one of my Solaris 10 box, CPU usage shows 100% using "sar", "vmstat". However, it has 4 CPUs and prstat and glance are not showing enough processes to justify high CPU utilization.
=========================================================================
$ prstat -a
... (4 Replies)
Hi,
We have a filesystem mystery on our hands. Given:
2 machines, A and Aa.
Machine Aa is the problem machine.
Machine A is running Ubuntu, kernel 2.6.22.9 #1 SMP Wed Feb 20 08:46:16 CST 2008 x86_64 GNU/Linux. Machine Aa is running RHEL5.3, kernel 2.6.18-128.el5 #1 SMP Wed Dec 17 11:41:38... (2 Replies)
Hi,
We have smb client running on two of the linux boxes and smb server on another linux system. During a backup operation which uses smb, read of a file was allowed while write to the same file was going on.Also simultaneous writes to the same file were allowed.Following are the settings in the... (1 Reply)
Hi guys,
I wrote a basic inotifywait shell script on my CentOS 5.6 x86_64 test server that syncs any deleted files in a directory.
/usr/bin/script
#!/bin/sh
inotifywait -m -e delete /home/user/test | while read file; do
# log event here
done
The script alone works fine. However, the... (4 Replies)
I have a set of requirement
1)cpu utilization on a server with pid and and process name.
It should display the above and also the script should have an option to record the cpu utilization for a given period of time
first part i can get with below commands
ps -eo pcpu,pid,user,args or... (5 Replies)
Hi All,
I have a script which does report the cpu usuage, there are few output parameter/fields displayed from the script. My problem is I have monitor the output and decide
which cpu number (column 2) has maximum value (column 6).
Since the output is displayed/updated every seconds, it's very... (1 Reply)
Hello Friends,
I am trying to create a shell script which will check the CPU utilization. I use command top to check the %CPU usage. It give s me below output
Cpu states:
CPU LOAD USER NICE SYS IDLE BLOCK SWAIT INTR SSYS
0 0.31 9.6% 0.0% 6.1% 84.3% 0.0% 0.0%... (3 Replies)
We have a single threaded application which is restricted by CPU usage even though there are multiple CPUs on the server, hence leading to significant performance issues. Is it possible to merge / combine multiple CPUs at OS level so it appear as a single CPU for the application? (6 Replies)
Hello experts,
we have input files with 700K lines each (one generated for every hour). and we need to convert them as below and move them to another directory once.
Sample INPUT:-
# cat test1
1559205600000,8474,NormalizedPortInfo,PctDiscards,0.0,Interface,BG-CTA-AX1.test.com,Vl111... (7 Replies)
Discussion started by: prvnrk
7 Replies
LEARN ABOUT REDHAT
urandom
RANDOM(4) Linux Programmer's Manual RANDOM(4)NAME
random, urandom - kernel random number source devices
DESCRIPTION
The character special files /dev/random and /dev/urandom (present since Linux 1.3.30) provide an interface to the kernel's random number
generator. File /dev/random has major device number 1 and minor device number 8. File /dev/urandom has major device number 1 and minor
device number 9.
The random number generator gathers environmental noise from device drivers and other sources into an entropy pool. The generator also
keeps an estimate of the number of bit of the noise in the entropy pool. From this entropy pool random numbers are created.
When read, the /dev/random device will only return random bytes within the estimated number of bits of noise in the entropy pool.
/dev/random should be suitable for uses that need very high quality randomness such as one-time pad or key generation. When the entropy
pool is empty, reads to /dev/random will block until additional environmental noise is gathered.
When read, /dev/urandom device will return as many bytes as are requested. As a result, if there is not sufficient entropy in the entropy
pool, the returned values are theoretically vulnerable to a cryptographic attack on the algorithms used by the driver. Knowledge of how to
do this is not available in the current non-classified literature, but it is theoretically possible that such an attack may exist. If this
is a concern in your application, use /dev/random instead.
CONFIGURING
If your system does not have /dev/random and /dev/urandom created already, they can be created with the following commands:
mknod -m 644 /dev/random c 1 8
mknod -m 644 /dev/urandom c 1 9
chown root:root /dev/random /dev/urandom
When a Linux system starts up without much operator interaction, the entropy pool may be in a fairly predictable state. This reduces the
actual amount of noise in the entropy pool below the estimate. In order to counteract this effect, it helps to carry entropy pool informa-
tion across shut-downs and start-ups. To do this, add the following lines to an appropriate script which is run during the Linux system
start-up sequence:
echo "Initializing kernel random number generator..."
# Initialize kernel random number generator with random seed
# from last shut-down (or start-up) to this start-up. Load and
# then save 512 bytes, which is the size of the entropy pool.
if [ -f /var/random-seed ]; then
cat /var/random-seed >/dev/urandom
fi
dd if=/dev/urandom of=/var/random-seed count=1
Also, add the following lines in an appropriate script which is run during the Linux system shutdown:
# Carry a random seed from shut-down to start-up for the random
# number generator. Save 512 bytes, which is the size of the
# random number generator's entropy pool.
echo "Saving random seed..."
dd if=/dev/urandom of=/var/random-seed count=1
FILES
/dev/random
/dev/urandom
AUTHOR
The kernel's random number generator was written by Theodore Ts'o (tytso@athena.mit.edu).
SEE ALSO
mknod (1)
RFC 1750, "Randomness Recommendations for Security"
Linux 1997-08-01 RANDOM(4)