Shantanu's Blog

Database Consultant

November 24, 2009

 

Manage logs

The default configuration file to manage logs is /etc/logrotate.conf:

# see "man logrotate" for details
# rotate log files weekly
weekly
# keep 4 weeks worth of backlogs
rotate 4
# create new (empty) log files after rotating old ones
create
# uncomment this if you want your log files compressed
#compress
# RPM packages drop log rotation information into this directory
include /etc/logrotate.d
# no packages own wtmp -- we'll rotate them here
/var/log/wtmp {
monthly
create 0664 root utmp
rotate 1
}

Service or server specific configurations stored in /etc/logrotate.d directory, for example here is sample apache logrotate configuration file:

/etc/logrotate.d/httpd

_____

Almost all logfiles are located under /var/log directory (and subdirectory).

* /var/log/cron.log: Crond logs (cron job)
* /var/log/maillog: Mail server logs
* /var/log/httpd/: Apache access and error logs directory
* /var/log/mysqld.log: MySQL database server log file
* /var/log/secure: Authentication log
* /var/log/yum.log: Yum log files

_____

A typical log rotate file for slow query log looks like this...

[root@server-db1 logrotate.d]# cat /etc/logrotate.d/mysqld
/var/lib/mysqllogs/slow-log {
daily
rotate 5
missingok
delaycompress
create 0640 mysql mysql
# skip 'notifempty'

postrotate
MYCNF_FILE=/root/.my.cnf
MYSQLADMIN=/usr/bin/mysqladmin
if test -x $MYSQLADMIN && \
$MYSQLADMIN --defaults-file="$MYCNF_FILE" ping >/dev/null
then
$MYSQLADMIN --defaults-file="$MYCNF_FILE" flush-logs
fi
endscript
}

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November 22, 2009

 

Introduction to PEAR - net URL2

Net_URL2 package helps you quickly process urls, without resorting to complex regular expressions or string manipulation.

http://pear.php.net/package/Net_URL2/

Here is how to use it...

?php
include('Net/URL2.php');
$url = new Net_URL2('http://www.some-domain.com:80/search.php?q=beatles&id=56&cat=music');
echo "Host : " . $url->host . "\n";
echo "Protocol : " . $url->scheme. "\n";
echo "Port : " . $url->port . "\n";
echo "Path : " . $url->path . "\n";
echo "Query Variables: \n";
print_r($url->QueryVariables);
?>


Which will output the following:

Host : www.some-domain.com
Protocol : http
Port : 80
Path : /search.php
Query String :
Array
(
[q] => beatles
[id] => 56
[cat] => music
)

http://www.codediesel.com/pear/easy-manipulation-of-urls-in-php/

Labels:


 

collation rules in full text search

I had discussed using collation rules to search unformatted telephone numbers.

http://oksoft.blogspot.com/search?q=character+set
Using collation rules in your Application

Today, we will see how you can use collation sets in the full text search.

First, find your character set files. Typically they’re under [MySQL Install Path]\share\charsets, but you can double check that with SHOW VARIABLES LIKE 'character_sets_dir';

Edit Index.xml. Find the section for the character set you want to use (I’m using latin1), and add a new collation, with a new name and an unused id:


Edit the character set file (latin1.xml in my example). Near the top you’ll find a array. There’s a leading 00 (which is there to offset the array to 257 characters for some legacy EOF convention, per the manual.) After that, you’ll find 256 bytes which identify the type of each character in the set. Find the hex value for the character you want (MySQL’s HEX() function is handy for this.) The value for “:” is 0×3A. Find that position in the array. Remember to start at 0×00, so 0×3A is the fourth row down, and the eleventh in from the left. Change the 10 there (which means spacing character) to 01 (which means upper case letter.) You’ll find the rest of the possible character types in the manual.

Scroll down in the same file and find the collations. Copy and paste the whole map from whichever one you normally use (like latin1_swedish_ci) and change the name to match the one we created in the Index.xml file (like latin1_ft_ci).

http://thenoyes.com/littlenoise/?p=91

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November 19, 2009

 

Disk Full Notification

The following shell script will notify you when the disk is almost full.
1) The curl will allow you to SMS an alert to your mobile
2) You will also get a mail to any address provided sendmail is enabled. Do not forget to change the ADMIN variable to your own email.
3) An alert is saved in a text file. Do not forget to check the file disk.txt from /home/develop folder!

Run this script every hour using cron:



#!/bin/sh
# disk space crontab entry to check disk every hour
# if any partition is full more than 95% defaults to 80%
# 15 * * * * /bin/sh -xv /root/disk-alert/disk1.sh 90 1>/root/disk-alert/log/disk_alert_succ.txt 2>>/root/disk-alert/log/disk_alert_err.txt


# change the path for output files
path='/root/disk-alert/log'
mailfile="/root/disk-alert/log/mail.txt"

# alert email with hostname alias
myhostname=`hostname`
ADMIN="shantanu.oak+$myhostname@gmail.com"
ADMIN1="abc@company.com"
ADMIN2="support@website.com"

# alert mobile number
number1='01234567890'
number2='09876543210'

# set alert level 80% as default if no user input found
ALERT=${1:-90}
mydate=`date '+%d %b %H:%M'`

df -HP | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $1 }' | while read output;
do
echo $output
usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1 )
partition=$(echo $output | awk '{ print $2 }' )
if [ $usep -ge $ALERT ]; then
# the message that will be written to a file, mail, SMS, Pop-up

# the word space is black listed by SMS gateway
mymessage="$(hostname) running out of disk $usep percent full of $partition as on $mydate"
echo "$mymessage" > $mailfile
echo "***files consuming more than 400 MB disk space *************" >> $mailfile

find / -type f -size +400000k -exec ls -lh {} \; | awk '{ print $9 ": " $5 }' >> $mailfile

echo "***Users consuming more space *************" >> $mailfile
cd /home/ && du -sm */ | sort -k1,1n | awk '$1 > 500 { sub(/$/, " MB", $1); print $0 }' >> $mailfile

# write to a file and email
echo "$mymessage" >> $path/disk.txt 2>> $path/disk_err.txt
cat $mailfile | mail -s "$myhostname disk full " $ADMIN, $ADMIN1, $ADMIN2

# sms alert add as many numbers as you want to the list
while read mnumber
do
curl -Ld'user=shantanu123@gmail.com:PassWd&state=4&senderID=TEST SMS&receipientno='$mnumber'&msgtxt='"'$mymessage'"'' http://api.mVaayoo.com/mvaayooapi/MessageCompose

done << mnumber_list
$number1
$number2
mnumber_list

# pop-up not applicable
# DISPLAY=:0 notify-send "Disk above 80% FULL"

fi
done


Command to find big files excluding docker and mount directory:

find . -type d \(  -path "./var/lib/docker/*" -o -path "./mnt/*" \)  -prune -o  -type f -size +400000k -exec ls -lh {} \; | awk '{ print $9 ": " $5 }'

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November 14, 2009

 

Using rsync to resume an interrupted file copy

If the network connection fails while "scp"ing the file from remote server to the central server, you have to start all over again. So why not to use rsync instead of scp? Here is a file that took 2 minutes to transfer. I stopped the transfer after 1 minute and then resumed it again with the same command. And it completes the job without reinitaing the full transfer.

$ time rsync --archive --recursive --compress --partial --progress --append root@123.123.123.123:/backup/somefile.txt.bz2 /home/ubuntu/
root@123.123.123.123's password:
receiving file list ...
1 file to consider
somefile.txt.bz2
rsync error: unexplained error (code 130) at rsync.c(271) [generator=2.6.9]
rsync error: received SIGUSR1 (code 19) at main.c(1182) [receiver=2.6.9]

real 1m16.258s
user 0m0.092s
sys 0m0.056s
_____

$ time rsync --archive --recursive --compress --partial --progress --append root@123.123.123.123:/backup/somefile.txt.bz2 /home/ubuntu/
root@123.123.123.123's password:
receiving file list ...
1 file to consider
somefile.txt.bz2
4398997 100% 169.46kB/s 0:00:25 (xfer#1, to-check=0/1)

sent 42 bytes received 2302738 bytes 29713.29 bytes/sec
total size is 4398997 speedup is 1.91

real 1m17.166s
user 0m0.128s
sys 0m0.036s

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November 02, 2009

 

changing mode of my.cnf

If I keep the file my.cnf world writable (777), then I get an error
Warning: World-writable config file '/etc/my.cnf' is ignored

The solution is to change the mod to 770 and start mysqld as root.

# ls my*.* -lht
-rw-rw-rw- 1 root root 1.3K Nov 4 10:54 my.cnf
-rw-r--r-- 1 root root 515 Oct 6 12:41 my_old.cnf

# chmod 770 my.cnf

# ls my*.* -lht
-rwxrwx--- 1 root root 1.3K Nov 4 10:54 my.cnf
-rw-r--r-- 1 root root 515 Oct 6 12:41 my_old.cnf

# service mysqld restart
Stopping MySQL: [ OK ]
Starting MySQL: [ OK ]

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