Linux Posts

Create a 1g 100MB 10Mb file for testing transfer speed

Published on Sunday, February 26th, 2012 in Linux.

Well yesterday I face another problem.
I have to try transfer speed from one client, because of complaining that his site is loading slow. After a short look on his server the load was below 1 on a quad core, the server didn’t swap, and didn’t have any slow mysql query.
Well last thing I wanted to see how is the bandwidth from that server . So how to create a large file fast ?
Well

dd

is the command from linux that i use.
So to create 1G file go with

dd if=/dev/zero of=testfile bs=1024 count=1024000

to create 100Mb try

dd if=/dev/zero of=testfile bs=1024 count=102400

and for 10Mb use

dd if=/dev/zero of=testfile bs=1024 count=10240

You can find on other forum that they use /dev/urandom or /dev/random however this are load intensive for your server and take longer to make the file.
So use /dev/zero for this purpose.

Automatically assign an Elastic IP at Launch time

Published on Thursday, February 23rd, 2012 in Linux.

Today I have face a problem . We want to have all time same ip on our instances because of some rules on a firewall. So how to add automatically elastic ip on a ec2 instance when start automaticaly by load balancer ?
Well this is not possible to be done automaticaly using amazon, so we have to wrote a bash script to be run on start up.

Here is the script:

#!/bin/bash
date
export EC2_HOME=/opt/aws/apitools/ec2-1.4.4.2
export JAVA_HOME=/usr/lib/jvm/jre
export CLASSPATH=${EC2_HOME}/lib
export EC2_PRIVATE_KEY=/root/pk.pem
export EC2_CERT=/root/cert.pem
export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/opt/aws/bin:/root/bin

ip=`/opt/aws/bin/ec2-describe-addresses -K /root/pk.pem -C /root/cert.pem |grep -v i-|head -1|awk {'print $2'}`
host=`hostname`
instance=`/opt/aws/bin/ec2-describe-instances -K /root/pk.pem -C /root/cert.pem  | grep $host |awk {'print $2'}`
runmore=`/opt/aws/bin/ec2-describe-addresses -K /root/pk.pem -C /root/cert.pem|grep $instance`

if [[ $runmore == '' ]];then
    if [[ $ip != '' ]];then
        /opt/aws/bin/ec2-associate-address -K /root/pk.pem -C /root/cert.pem -i $instance $ip
    fi
fi

Now all you have to do is to add this script on /etc/rc.d/rc.local to be run on startup . If your instance have a elastic ip asigned will not do anything, else will assing first free elastic ip.

EBS hangs in “attaching” mode

Published on Thursday, February 9th, 2012 in Linux.

Well with the script bellow automatic script for backup up redis on a amazon ebs
I saw that was a problem.
From time to time the ebs hang with “attaching”
And the mount command die in D state. And the load on that server grow.
Well, we have modify the script to wait for the volume to be actually “attached” .

This is a improvement version of the script.

#!/bin/bash
date
instance=i-xxxxx
volume=vol-xxxx
iplocalhost=10.00.00.111

export EC2_HOME=/path/ec2-1.4.4.2
export JAVA_HOME=/usr/lib/jvm/jre
export CLASSPATH=${EC2_HOME}/lib
export EC2_PRIVATE_KEY=/root/path/pk.pem
export EC2_CERT=/root/path/cert.pem
export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/opt/aws/bin:/root/bin

if [ ! -d /mnt/backup ]; then
mkdir /mnt/backup
fi

if [ ! -f /tmp/redis1 ]; then
echo "Cron Started"
touch /tmp/redis1
else
echo "Cron already running"
exit 0
fi
atached=1
while [ $atached -eq 1 ];do
echo "">/root/status.txt
/opt/aws/bin/ec2-describe-volumes -K /root/path/pk.pem -C /root/path/cert.pem > /root/status.txt
if grep -q "available" "/root/status.txt" ; then
echo "Volume is available."
echo "Attaching Volume"
/opt/aws/bin/ec2-attach-volume -K /root/path/pk.pem -C /root/path/cert.pem $volume -i $instance -d /dev/sdh
atached=0
else
echo "Volume is already attached on other instance. Sleeping for 60 seconds"
sleep 60
fi
done
avaiable=1
COUNTER=1
while [ $avaiable -eq 1 ];do
/opt/aws/bin/ec2-describe-volumes -K /root/path/pk.pem -C /root/path/cert.pem $volume > /root/status.txt
if grep -q "attached" "/root/status.txt" ; then
echo "Volume is attached."
avaiable=0
echo "Mounting Volume"
mount /dev/sdh /mnt/backup
sleep 10
if [ -f /mnt/backup/montat ]; then
rsync -vrplogDtH /var/lib/redis/ /mnt/backup/redis
fi
else
echo "Volume is attaching. Sleeping for 60 seconds"
sleep 60
fi
if [ $COUNTER -eq 5 ]; then
echo "Quiting ater 5 minutes"
break
fi
let COUNTER+=1
done
umount -lf /mnt/backup
sleep 5
/opt/aws/bin/ec2-detach-volume -f -K /root/path/pk.pem -C /root/path/cert.pem $volume -i $instance -d /dev/sdh
sleep 5
rm -rf /tmp/redis1
exit;

service php-fpm restart with error after upgrade from 5.3.8 to 5.3.10

Published on Tuesday, February 7th, 2012 in Linux.

Well
I have to upgrade a server from php 5.3.8 to 5.3.10 on a centos server.
After this the service php-fpm restart didn’t work.

Stopping php-fpm:                                          [FAILED]

So after a short look to the problem, what I discover is that problem is on this file

/etc/init.d/php-fpm

What I have was

pidfile=${PIDFILE-/var/run/php-fpm/php-fpm.pid}

and this line should be

pidfile=${PIDFILE-/var/run/php-fpm.pid}

search files with multiple patterns in linux

Published on Thursday, January 26th, 2012 in Linux.

Well today I have to search files with *.php and with *.html .

How to do that ?

Solution is :

find ./  \( -name "*.php" -o -name "*.html"   \)

 

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