Wednesday 29 February 2012

How to get the Disk informations in linux


# hdparm -I /dev/sda  ------ information about the IDE/ATA disk (Linux) / disk performance
# fdisk /dev/sda6        ------ Display and manipulate the partition table
# smartctl -a /dev/sda1 --- Display the disk SMART info
# diskinfo -v /dev/ad2 ---- information about disk (sector/size) FreeBSD
# dmidecode               -------  dmidecode  is  a  tool for dumping a computer’s DMI(some say SMBIOS) table contents in a human-readable format. This table contains a description of the system’s hardware components.

To find the mounted file system in our system

# mount | column -t


Singnals in Linux

Terminate or send a signal with kill or killall

# kill -s TERM 4712  -------- same as kill -15 4712
# killall -1 httpd    -------- Kill HUP processes by exact name
# pkill -9 http          -------- Kill TERM processes by (part of) name
# pkill -TERM -u www ------- Kill TERM processes owned by www
# fuser -k -TERM -m /home ------ Kill every process accessing /home
                                                           (to umount)


Important signals are:

-1  HUP (hang up)
-2  INT (interrupt)
-3  QUIT (quit)
-9  KILL (non-catchable, non-ignorable kill)
-15 TERM (software termination signal)
















How to set a process Priority in Linux

Change the priority of a running process with nice and renice. Negative numbers have a higher priority, the lowest is -20 and "nice" have a positive value.

 # renice -5 586   ------ stronger priority

 Start the process with a defined priority with nice. Positive is "nice" or weak, negative is strong scheduling priority.

# nice -n -5 top   # Stronger priority (/usr/bin/nice)

# nice -n 5 top      # Weaker priority (/usr/bin/nice)
# nice +5 top

While nice changes the CPU scheduler, an other useful command ionice will schedule the disk IO. This is very useful for intensive IO application.


# ionice c3 -p123 # set idle class for pid 123

# ionice -c2 -n0 firefox # Run firefox with best effort and
                                             high priority
# ionice -c3 -p$$ # Set the actual shell to idle priority

nohup

Use nohup to start a process which has to keep running when the shell is closed

# nohup  sh run.sh  -b 0.0.0.0 &
# nohup ping -i 60 > ping.log &

 

 

 
















Monday 27 February 2012

How to Take backup of MBR

Follow the steps to taking backup of MBR

# sfdisk -d /dev/sda > sda.out

 # cat sda.out
    # partition table of /dev/sda
unit: sectors

/dev/sda1 : start=       63, size=480134592, Id=83, bootable
/dev/sda2 : start=480134655, size=  8257410, Id=82
/dev/sda3 : start=        0, size=        0, Id= 0
/dev/sda4 : start=        0, size=        0, Id= 0

 To restore it

# sfdisk /dev/sda < sda.out

Or you can take the backup and restore grub using dd command.

Backup
# dd if=/dev/sda of=grub.bkp bs=512 count=1

Restore
# dd if=grub.bkp of=/dev/sda bs=512 count=1




 

How to Repair a broken Grub

First Boot from a live cd, mount the linux partition, add /proc and /dev and use grub-install  /dev/xyz. Suppose linux lies on /dev/sda6:


# mount /dev/sda6 /mnt   ------ mount the linux partition on /mnt

# mount --bind /proc /mnt/proc ----- mount the proc subsystem into /mnt

# mount --bind /dev /mnt/dev ------- mount the devices into /mnt

# chroot /mnt  ---------- change root to the linux partition

# grub-install /dev/sda -------- reinstall grub with your old settings




Useful linux commands

# id  ---------- Show the active user id with login and group

# id username ---------- Shows details for a particular user

last  ----------- Show last logins on the system

# who  --------- Show who is logged on the system

# who -u ------- shows the pid also of the logged in user, so easy to kill that particular user only. # kill -9 PID

# useradd -c "Colin Barschel" -g admin -m colin  ----- all in one line

ulimit -a
The shell limits are governed by ulimit. The status is checked with ulimit -a,
To change the open files limit from 1024 to 10240 do:
# ulimit -n 10240    , This is only valid within the shell.

 Login users and applications can be configured in /etc/security/limits.conf

# cat /etc/security/limits.conf
*  hard  nproc 250  # Limit user processes
asterisk  hard  nofile  409600 # Limit application open files

Use chkconfig to configure the programs that will be started at boot in a runlevel.

# chkconfig --list  ------- List all init scripts
# chkconfig --list sshd ----- Report the status of sshd
# chkconfig sshd --level 35 on ------ Configure sshd for levels 3 and 5
# chkconfig sshd off  -------- Disable sshd for all runlevels

Some Kernel Modules

#  lsmod  -------- List all modules loaded in the kernel
# rmmode --------  To remove a module
# modprobe usb-storage --------- To load a module
# insmod ----- To load a module 





Sunday 26 February 2012

TOP Command Help in linux



# top

Line1: Gives System present time, up time of the machine, number of users logged in, Load average on system at 5, 10, 15 min interval.

Line2: Gives total number of process on the machine, number of running process, number of sleeping process, number of stopped process, number of Zambie process.

Line3: Gives you CPU details

Line4 & 5: Gives RAM and SWAP details.

Line6: To execute top command shortcuts

From Line7: dynamically displayed top process results.

l --To display or to hide load average line
t --To display or to hide task/cpu line
1 --To display or hide all other CPU's
m --to display or to hide RAM and SWAP details
s --To change the time interval for updating top results(value is in sec's)
R --To sort by PID number
u -- Press u then username to get only that user process details
P --To sort by CPU utilization
M --To sort by RAM utilization
c --To display or hide command full path
r --To renice a process, press r then the PID no then the renice value to renice a process.
k --To kill a process, press k then PID number then enter to kill a process
w --To save the modified configuration permanently.
q --To quit the top command.
h --for getting help on top command

System Load and Statistics

# top  -------- display and update the top cpu processes

# mpstat 1  ---------- display processors related statistics

# vmstat 2  ---------- display virtual memory statistics

# iostat 2    ---------- display I/O statistics

For checking system load we can also use

# uptime   and

# w

Hardware Informations

# dmesg  ---------- Detected hardware and boot messages

# dd if=/dev/mem bs=1k skip=768 count=256 2>/dev/null | strings -n 8 ----------
 Read BIOS

cat /proc/cpuinfo  ---------- CPU model / informations

# cat /proc/meminfo ---------- Hardware memory

# watch -n1 'cat /proc/interrupts'  ---------- Watch changeable interrupts continuously

# free -m  ---------- Used and free memory
# vmstat

# cat /proc/devices  ---------- Configured devices

# lspci    ---------- list all PCI devices, it shows Ethernet card manufacturer etc.

lsusb  ---------- list USB devices.

lshal  ---------- Show a list of all devices with their properties

# dmidecode  ---------- Show DMI/SMBIOS: hw info from the BIOS

sysctl vm   ---------- Memory usage

# sysctl  ---------- read/write system parameters, configure kernel parameters at runtime.

# sysctl -a | grep mem  ---------- Kernel memory settings and info

# sysctl dev  ---------- Configured devices


System Related Informations

# uname -r    -------- print the kernel release
2.6.18-164.el5

# uname -i     --------- print the hardware platform
i386

# uname -o    --------- print the operating system
GNU/Linux

# uname -s    --------- print the kernel name
Linux

# cat /etc/issue -------- Show OS version
CentOS release 5.4 (Final)

# uptime           -------- Show how long the system has been running + load
15:52:07 up 5 days,  6:36,  3 users,  load average: 0.04, 0.06, 0.02

# hostname      ------- system's host name
cloudcc.ctechz.blogspot.com

# hostname -i   ------- Display the IP address of the host.

# man hier       ------- Description of the file system hierarchy

# last reboot  ------- Show system reboot history





Wednesday 8 February 2012

Pearl Script for mysql DB health Check


#!/usr/bin/perl -w

use strict;
use warnings;
use diagnostics;
use File::Spec;
use Getopt::Long;

# Set up a few variables for use in the script
my $tunerversion = "1.2.0";
my (@adjvars, @generalrec);

# Set defaults
my %opt = (
"nobad" => 0,
"nogood" => 0,
"noinfo" => 0,
"nocolor" => 0,
"forcemem" => 0,
"forceswap" => 0,
"host" => 0,
"socket" => 0,
"port" => 0,
"user" => 0,
"pass" => 0,
"skipsize" => 0,
"checkversion" => 0,
);

# Gather the options from the command line
GetOptions(\%opt,
'nobad',
'nogood',
'noinfo',
'nocolor',
'forcemem=i',
'forceswap=i',
'host=s',
'socket=s',
'port=i',
'user=s',
'pass=s',
'skipsize',
'checkversion',
'help',
);

if (defined $opt{'help'} && $opt{'help'} == 1) { usage(); }

sub usage {
# Shown with --help option passed
print "\n".
" MySQLTuner $tunerversion - MySQL High Performance Tuning Script\n".
"\n".
" Important Usage Guidelines:\n".
" To run the script with the default options, run the script without arguments\n".
" Allow MySQL server to run for at least 24-48 hours before trusting suggestions\n".
" Some routines may require root level privileges (script will provide warnings)\n".
" You must provide the remote server's total memory when connecting to other servers\n".
"\n".
" Connection and Authentication\n".
" --host <hostname> Connect to a remote host to perform tests (default: localhost)\n".
" --socket <socket> Use a different socket for a local connection\n".
" --port <port> Port to use for connection (default: 3306)\n".
" --user <username> Username to use for authentication\n".
" --pass <password> Password to use for authentication\n".
"\n".
" Performance and Reporting Options\n".
" --skipsize Don't enumerate tables and their types/sizes (default: on)\n".
" (Recommended for servers with many tables)\n".
" --checkversion Check for updates to MySQLTuner (default: don't check)\n".
" --forcemem <size> Amount of RAM installed in megabytes\n".
" --forceswap <size> Amount of swap memory configured in megabytes\n".
"\n".
" Output Options:\n".
" --nogood Remove OK responses\n".
" --nobad Remove negative/suggestion responses\n".
" --noinfo Remove informational responses\n".
" --nocolor Don't print output in color\n".
"\n";
exit;
}

my $devnull = File::Spec->devnull();

# Setting up the colors for the print styles
my $good = ($opt{nocolor} == 0)? "[\e[0;32mOK\e[0m]" : "[OK]" ;
my $bad = ($opt{nocolor} == 0)? "[\e[0;31m!!\e[0m]" : "[!!]" ;
my $info = ($opt{nocolor} == 0)? "[\e[0;34m--\e[0m]" : "[--]" ;

# Functions that handle the print styles
sub goodprint { print $good." ".$_[0] unless ($opt{nogood} == 1); }
sub infoprint { print $info." ".$_[0] unless ($opt{noinfo} == 1); }
sub badprint { print $bad." ".$_[0] unless ($opt{nobad} == 1); }
sub redwrap { return ($opt{nocolor} == 0)? "\e[0;31m".$_[0]."\e[0m" : $_[0] ; }
sub greenwrap { return ($opt{nocolor} == 0)? "\e[0;32m".$_[0]."\e[0m" : $_[0] ; }

# Calculates the parameter passed in bytes, and then rounds it to one decimal place
sub hr_bytes {
my $num = shift;
if ($num >= (1024**3)) { #GB
return sprintf("%.1f",($num/(1024**3)))."G";
} elsif ($num >= (1024**2)) { #MB
return sprintf("%.1f",($num/(1024**2)))."M";
} elsif ($num >= 1024) { #KB
return sprintf("%.1f",($num/1024))."K";
} else {
return $num."B";
}
}

# Calculates the parameter passed in bytes, and then rounds it to the nearest integer
sub hr_bytes_rnd {
my $num = shift;
if ($num >= (1024**3)) { #GB
return int(($num/(1024**3)))."G";
} elsif ($num >= (1024**2)) { #MB
return int(($num/(1024**2)))."M";
} elsif ($num >= 1024) { #KB
return int(($num/1024))."K";
} else {
return $num."B";
}
}

# Calculates the parameter passed to the nearest power of 1000, then rounds it to the nearest integer
sub hr_num {
my $num = shift;
if ($num >= (1000**3)) { # Billions
return int(($num/(1000**3)))."B";
} elsif ($num >= (1000**2)) { # Millions
return int(($num/(1000**2)))."M";
} elsif ($num >= 1000) { # Thousands
return int(($num/1000))."K";
} else {
return $num;
}
}

# Calculates uptime to display in a more attractive form
sub pretty_uptime {
my $uptime = shift;
my $seconds = $uptime % 60;
my $minutes = int(($uptime % 3600) / 60);
my $hours = int(($uptime % 86400) / (3600));
my $days = int($uptime / (86400));
my $uptimestring;
if ($days > 0) {
$uptimestring = "${days}d ${hours}h ${minutes}m ${seconds}s";
} elsif ($hours > 0) {
$uptimestring = "${hours}h ${minutes}m ${seconds}s";
} elsif ($minutes > 0) {
$uptimestring = "${minutes}m ${seconds}s";
} else {
$uptimestring = "${seconds}s";
}
return $uptimestring;
}

# Retrieves the memory installed on this machine
my ($physical_memory,$swap_memory,$duflags);
sub os_setup {
sub memerror {
badprint "Unable to determine total memory/swap; use '--forcemem' and '--forceswap'\n";
exit;
}
my $os = `uname`;
$duflags = ($os =~ /Linux/) ? '-b' : '';
if ($opt{'forcemem'} > 0) {
$physical_memory = $opt{'forcemem'} * 1048576;
infoprint "Assuming $opt{'forcemem'} MB of physical memory\n";
if ($opt{'forceswap'} > 0) {
$swap_memory = $opt{'forceswap'} * 1048576;
infoprint "Assuming $opt{'forceswap'} MB of swap space\n";
} else {
$swap_memory = 0;
badprint "Assuming 0 MB of swap space (use --forceswap to specify)\n";
}
} else {
if ($os =~ /Linux/) {
$physical_memory = `free -b | grep Mem | awk '{print \$2}'` or memerror;
$swap_memory = `free -b | grep Swap | awk '{print \$2}'` or memerror;
} elsif ($os =~ /Darwin/) {
$physical_memory = `sysctl -n hw.memsize` or memerror;
$swap_memory = `sysctl -n vm.swapusage | awk '{print \$3}' | sed 's/\..*\$//'` or memerror;
} elsif ($os =~ /NetBSD|OpenBSD/) {
$physical_memory = `sysctl -n hw.physmem` or memerror;
if ($physical_memory < 0) {
$physical_memory = `sysctl -n hw.physmem64` or memerror;
}
$swap_memory = `swapctl -l | grep '^/' | awk '{ s+= \$2 } END { print s }'` or memerror;
} elsif ($os =~ /BSD/) {
$physical_memory = `sysctl -n hw.realmem`;
$swap_memory = `swapinfo | grep '^/' | awk '{ s+= \$2 } END { print s }'`;
} elsif ($os =~ /SunOS/) {
$physical_memory = `/usr/sbin/prtconf | grep Memory | cut -f 3 -d ' '` or memerror;
chomp($physical_memory);
$physical_memory = $physical_memory*1024*1024;
} elsif ($os =~ /AIX/) {
$physical_memory = `lsattr -El sys0 | grep realmem | awk '{print \$2}'` or memerror;
chomp($physical_memory);
$physical_memory = $physical_memory*1024;
$swap_memory = `lsps -as | awk -F"(MB| +)" '/MB /{print \$2}'` or memerror;
chomp($swap_memory);
$swap_memory = $swap_memory*1024*1024;
}
}
chomp($physical_memory);
}

# Checks to see if a MySQL login is possible
my ($mysqllogin,$doremote,$remotestring);
sub mysql_setup {
$doremote = 0;
$remotestring = '';
my $command = `which mysqladmin`;
chomp($command);
if (! -e $command) {
badprint "Unable to find mysqladmin in your \$PATH. Is MySQL installed?\n";
exit;
}

# Are we being asked to connect via a socket?
if ($opt{socket} ne 0) {
$remotestring = " -S $opt{socket}";
}

# Are we being asked to connect to a remote server?
if ($opt{host} ne 0) {
chomp($opt{host});
$opt{port} = ($opt{port} eq 0)? 3306 : $opt{port} ;

# If we're doing a remote connection, but forcemem wasn't specified, we need to exit
if ($opt{'forcemem'} eq 0) {
badprint "The --forcemem option is required for remote connections\n";
exit;
}
infoprint "Performing tests on $opt{host}:$opt{port}\n";
$remotestring = " -h $opt{host} -P $opt{port}";
$doremote = 1;
}

# Did we already get a username and password passed on the command line?
if ($opt{user} ne 0 and $opt{pass} ne 0) {
$mysqllogin = "-u $opt{user} -p'$opt{pass}'".$remotestring;
my $loginstatus = `mysqladmin ping $mysqllogin 2>&1`;
if ($loginstatus =~ /mysqld is alive/) {
goodprint "Logged in using credentials passed on the command line\n";
return 1;
} else {
badprint "Attempted to use login credentials, but they were invalid\n";
exit 0;
}
}
if ( -r "/etc/psa/.psa.shadow" and $doremote == 0 ) {
# It's a Plesk box, use the available credentials
$mysqllogin = "-u admin -p`cat /etc/psa/.psa.shadow`";
my $loginstatus = `mysqladmin ping $mysqllogin 2>&1`;
unless ($loginstatus =~ /mysqld is alive/) {
badprint "Attempted to use login credentials from Plesk, but they failed.\n";
exit 0;
}
} elsif ( -r "/etc/mysql/debian.cnf" and $doremote == 0 ){
# We have a debian maintenance account, use it
$mysqllogin = "--defaults-file=/etc/mysql/debian.cnf";
my $loginstatus = `mysqladmin $mysqllogin ping 2>&1`;
if ($loginstatus =~ /mysqld is alive/) {
goodprint "Logged in using credentials from debian maintenance account.\n";
return 1;
} else {
badprint "Attempted to use login credentials from debian maintenance account, but they failed.\n";
exit 0;
}
} else {
# It's not Plesk or debian, we should try a login
my $loginstatus = `mysqladmin $remotestring ping 2>&1`;
if ($loginstatus =~ /mysqld is alive/) {
# Login went just fine
$mysqllogin = " $remotestring ";

# Did this go well because of a .my.cnf file or is there no password set?
my $userpath = `printenv HOME`;
if (length($userpath) > 0) {
chomp($userpath);
}
unless ( -e "${userpath}/.my.cnf" ) {
badprint "Successfully authenticated with no password - SECURITY RISK!\n";
}
return 1;
} else {
print STDERR "Please enter your MySQL administrative login: ";
my $name = <>;
print STDERR "Please enter your MySQL administrative password: ";
system("stty -echo >$devnull 2>&1");
my $password = <>;
system("stty echo >$devnull 2>&1");
chomp($password);
chomp($name);
$mysqllogin = "-u $name";
if (length($password) > 0) {
$mysqllogin .= " -p'$password'";
}
$mysqllogin .= $remotestring;
my $loginstatus = `mysqladmin ping $mysqllogin 2>&1`;
if ($loginstatus =~ /mysqld is alive/) {
print STDERR "\n";
if (! length($password)) {
# Did this go well because of a .my.cnf file or is there no password set?
my $userpath = `ls -d ~`;
chomp($userpath);
unless ( -e "$userpath/.my.cnf" ) {
badprint "Successfully authenticated with no password - SECURITY RISK!\n";
}
}
return 1;
} else {
print "\n".$bad." Attempted to use login credentials, but they were invalid.\n";
exit 0;
}
exit 0;
}
}
}

# Populates all of the variable and status hashes
my (%mystat,%myvar,$dummyselect);
sub get_all_vars {
# We need to initiate at least one query so that our data is useable
$dummyselect = `mysql $mysqllogin -Bse "SELECT VERSION();"`;
my @mysqlvarlist = `mysql $mysqllogin -Bse "SHOW /*!50000 GLOBAL */ VARIABLES;"`;
foreach my $line (@mysqlvarlist) {
$line =~ /([a-zA-Z_]*)\s*(.*)/;
$myvar{$1} = $2;
}
my @mysqlstatlist = `mysql $mysqllogin -Bse "SHOW /*!50000 GLOBAL */ STATUS;"`;
foreach my $line (@mysqlstatlist) {
$line =~ /([a-zA-Z_]*)\s*(.*)/;
$mystat{$1} = $2;
}
# Workaround for MySQL bug #59393 wrt. ignore-builtin-innodb
if (($myvar{'ignore_builtin_innodb'} || "") eq "ON") {
$myvar{'have_innodb'} = "NO";
}

# have_* for engines is deprecated and will be removed in MySQL 5.6;
# check SHOW ENGINES and set corresponding old style variables.
# Also works around MySQL bug #59393 wrt. skip-innodb
my @mysqlenginelist = `mysql $mysqllogin -Bse "SHOW ENGINES;" 2>$devnull`;
foreach my $line (@mysqlenginelist) {
if ($line =~ /^([a-zA-Z_]+)\s+(\S+)/) {
my $engine = lc($1);
if ($engine eq "federated" || $engine eq "blackhole") {
$engine .= "_engine";
} elsif ($engine eq "berkeleydb") {
$engine = "bdb";
}
my $val = ($2 eq "DEFAULT") ? "YES" : $2;
$myvar{"have_$engine"} = $val;
}
}
}

sub security_recommendations {
print "\n-------- Security Recommendations -------------------------------------------\n";
my @mysqlstatlist = `mysql $mysqllogin -Bse "SELECT CONCAT(user, '\@', host) FROM mysql.user WHERE password = '' OR password IS NULL;"`;
if (@mysqlstatlist) {
foreach my $line (sort @mysqlstatlist) {
chomp($line);
badprint "User '".$line."' has no password set.\n";
}
} else {
goodprint "All database users have passwords assigned\n";
}
}

sub get_replication_status {
my $slave_status = `mysql $mysqllogin -Bse "show slave status\\G"`;
my ($io_running) = ($slave_status =~ /slave_io_running\S*\s+(\S+)/i);
my ($sql_running) = ($slave_status =~ /slave_sql_running\S*\s+(\S+)/i);
if ($io_running eq 'Yes' && $sql_running eq 'Yes') {
if ($myvar{'read_only'} eq 'OFF') {
badprint "This replication slave is running with the read_only option disabled.";
} else {
goodprint "This replication slave is running with the read_only option enabled.";
}
}
}

# Checks for updates to MySQLTuner
sub validate_tuner_version {
print "\n-------- General Statistics --------------------------------------------------\n";
if ($opt{checkversion} eq 0) {
infoprint "Skipped version check for MySQLTuner script\n";
return;
}
my $update;
my $url = "http://mysqltuner.com/versioncheck.php?v=$tunerversion";
if (-e "/usr/bin/curl") {
$update = `/usr/bin/curl --connect-timeout 5 '$url' 2>$devnull`;
chomp($update);
} elsif (-e "/usr/bin/wget") {
$update = `/usr/bin/wget -e timestamping=off -T 5 -O - '$url' 2>$devnull`;
chomp($update);
}
if ($update eq 1) {
badprint "There is a new version of MySQLTuner available\n";
} elsif ($update eq 0) {
goodprint "You have the latest version of MySQLTuner\n";
} else {
infoprint "Unable to check for the latest MySQLTuner version\n";
}
}

# Checks for supported or EOL'ed MySQL versions
my ($mysqlvermajor,$mysqlverminor);
sub validate_mysql_version {
($mysqlvermajor,$mysqlverminor) = $myvar{'version'} =~ /(\d)\.(\d)/;
if (!mysql_version_ge(5)) {
badprint "Your MySQL version ".$myvar{'version'}." is EOL software! Upgrade soon!\n";
} elsif (mysql_version_ge(6)) {
badprint "Currently running unsupported MySQL version ".$myvar{'version'}."\n";
} else {
goodprint "Currently running supported MySQL version ".$myvar{'version'}."\n";
}
}

# Checks if MySQL version is greater than equal to (major, minor)
sub mysql_version_ge {
my ($maj, $min) = @_;
return $mysqlvermajor > $maj || ($mysqlvermajor == $maj && $mysqlverminor >= ($min || 0));
}

# Checks for 32-bit boxes with more than 2GB of RAM
my ($arch);
sub check_architecture {
if ($doremote eq 1) { return; }
if (`uname` =~ /SunOS/ && `isainfo -b` =~ /64/) {
$arch = 64;
goodprint "Operating on 64-bit architecture\n";
} elsif (`uname` !~ /SunOS/ && `uname -m` =~ /64/) {
$arch = 64;
goodprint "Operating on 64-bit architecture\n";
} elsif (`uname` =~ /AIX/ && `bootinfo -K` =~ /64/) {
$arch = 64;
goodprint "Operating on 64-bit architecture\n";
} else {
$arch = 32;
if ($physical_memory > 2147483648) {
badprint "Switch to 64-bit OS - MySQL cannot currently use all of your RAM\n";
} else {
goodprint "Operating on 32-bit architecture with less than 2GB RAM\n";
}
}
}

# Start up a ton of storage engine counts/statistics
my (%enginestats,%enginecount,$fragtables);
sub check_storage_engines {
if ($opt{skipsize} eq 1) {
print "\n-------- Storage Engine Statistics -------------------------------------------\n";
infoprint "Skipped due to --skipsize option\n";
return;
}
print "\n-------- Storage Engine Statistics -------------------------------------------\n";
infoprint "Status: ";
my $engines;
$engines .= (defined $myvar{'have_archive'} && $myvar{'have_archive'} eq "YES")? greenwrap "+Archive " : redwrap "-Archive " ;
$engines .= (defined $myvar{'have_bdb'} && $myvar{'have_bdb'} eq "YES")? greenwrap "+BDB " : redwrap "-BDB " ;
$engines .= (defined $myvar{'have_federated_engine'} && $myvar{'have_federated_engine'} eq "YES")? greenwrap "+Federated " : redwrap "-Federated " ;
$engines .= (defined $myvar{'have_innodb'} && $myvar{'have_innodb'} eq "YES")? greenwrap "+InnoDB " : redwrap "-InnoDB " ;
$engines .= (defined $myvar{'have_isam'} && $myvar{'have_isam'} eq "YES")? greenwrap "+ISAM " : redwrap "-ISAM " ;
$engines .= (defined $myvar{'have_ndbcluster'} && $myvar{'have_ndbcluster'} eq "YES")? greenwrap "+NDBCluster " : redwrap "-NDBCluster " ;
print "$engines\n";
if (mysql_version_ge(5)) {
# MySQL 5 servers can have table sizes calculated quickly from information schema
my @templist = `mysql $mysqllogin -Bse "SELECT ENGINE,SUM(DATA_LENGTH),COUNT(ENGINE) FROM information_schema.TABLES WHERE TABLE_SCHEMA NOT IN ('information_schema','mysql') AND ENGINE IS NOT NULL GROUP BY ENGINE ORDER BY ENGINE ASC;"`;
foreach my $line (@templist) {
my ($engine,$size,$count);
($engine,$size,$count) = $line =~ /([a-zA-Z_]*)\s+(\d+)\s+(\d+)/;
if (!defined($size)) { next; }
$enginestats{$engine} = $size;
$enginecount{$engine} = $count;
}
$fragtables = `mysql $mysqllogin -Bse "SELECT COUNT(TABLE_NAME) FROM information_schema.TABLES WHERE TABLE_SCHEMA NOT IN ('information_schema','mysql') AND Data_free > 0 AND NOT ENGINE='MEMORY';"`;
chomp($fragtables);
} else {
# MySQL < 5 servers take a lot of work to get table sizes
my @tblist;

# Now we build a database list, and loop through it to get storage engine stats for tables
my @dblist = `mysql $mysqllogin -Bse "SHOW DATABASES"`;
foreach my $db (@dblist) {
chomp($db);
if ($db eq "information_schema") { next; }
my @ixs = (1, 6, 9);
if (!mysql_version_ge(4, 1)) {
# MySQL 3.23/4.0 keeps Data_Length in the 5th (0-based) column
@ixs = (1, 5, 8);
}
push(@tblist, map { [ (split)[@ixs] ] } `mysql $mysqllogin -Bse "SHOW TABLE STATUS FROM \\\`$db\\\`"`);
}

# Parse through the table list to generate storage engine counts/statistics
$fragtables = 0;
foreach my $tbl (@tblist) {
my ($engine, $size, $datafree) = @$tbl;
if (defined $enginestats{$engine}) {
$enginestats{$engine} += $size;
$enginecount{$engine} += 1;
} else {
$enginestats{$engine} = $size;
$enginecount{$engine} = 1;
}
if ($datafree > 0) {
$fragtables++;
}
}
}
while (my ($engine,$size) = each(%enginestats)) {
infoprint "Data in $engine tables: ".hr_bytes_rnd($size)." (Tables: ".$enginecount{$engine}.")"."\n";
}

# If the storage engine isn't being used, recommend it to be disabled
if (!defined $enginestats{'InnoDB'} && defined $myvar{'have_innodb'} && $myvar{'have_innodb'} eq "YES") {
badprint "InnoDB is enabled but isn't being used\n";
push(@generalrec,"Add skip-innodb to MySQL configuration to disable InnoDB");
}
if (!defined $enginestats{'BerkeleyDB'} && defined $myvar{'have_bdb'} && $myvar{'have_bdb'} eq "YES") {
badprint "BDB is enabled but isn't being used\n";
push(@generalrec,"Add skip-bdb to MySQL configuration to disable BDB");
}
if (!defined $enginestats{'ISAM'} && defined $myvar{'have_isam'} && $myvar{'have_isam'} eq "YES") {
badprint "ISAM is enabled but isn't being used\n";
push(@generalrec,"Add skip-isam to MySQL configuration to disable ISAM (MySQL > 4.1.0)");
}

# Fragmented tables
if ($fragtables > 0) {
badprint "Total fragmented tables: $fragtables\n";
push(@generalrec,"Run OPTIMIZE TABLE to defragment tables for better performance");
} else {
goodprint "Total fragmented tables: $fragtables\n";
}
}

my %mycalc;
sub calculations {
if ($mystat{'Questions'} < 1) {
badprint "Your server has not answered any queries - cannot continue...";
exit 0;
}

# Per-thread memory
if (mysql_version_ge(4)) {
$mycalc{'per_thread_buffers'} = $myvar{'read_buffer_size'} + $myvar{'read_rnd_buffer_size'} + $myvar{'sort_buffer_size'} + $myvar{'thread_stack'} + $myvar{'join_buffer_size'};
} else {
$mycalc{'per_thread_buffers'} = $myvar{'record_buffer'} + $myvar{'record_rnd_buffer'} + $myvar{'sort_buffer'} + $myvar{'thread_stack'} + $myvar{'join_buffer_size'};
}
$mycalc{'total_per_thread_buffers'} = $mycalc{'per_thread_buffers'} * $myvar{'max_connections'};
$mycalc{'max_total_per_thread_buffers'} = $mycalc{'per_thread_buffers'} * $mystat{'Max_used_connections'};

# Server-wide memory
$mycalc{'max_tmp_table_size'} = ($myvar{'tmp_table_size'} > $myvar{'max_heap_table_size'}) ? $myvar{'max_heap_table_size'} : $myvar{'tmp_table_size'} ;
$mycalc{'server_buffers'} = $myvar{'key_buffer_size'} + $mycalc{'max_tmp_table_size'};
$mycalc{'server_buffers'} += (defined $myvar{'innodb_buffer_pool_size'}) ? $myvar{'innodb_buffer_pool_size'} : 0 ;
$mycalc{'server_buffers'} += (defined $myvar{'innodb_additional_mem_pool_size'}) ? $myvar{'innodb_additional_mem_pool_size'} : 0 ;
$mycalc{'server_buffers'} += (defined $myvar{'innodb_log_buffer_size'}) ? $myvar{'innodb_log_buffer_size'} : 0 ;
$mycalc{'server_buffers'} += (defined $myvar{'query_cache_size'}) ? $myvar{'query_cache_size'} : 0 ;

# Global memory
$mycalc{'max_used_memory'} = $mycalc{'server_buffers'} + $mycalc{"max_total_per_thread_buffers"};
$mycalc{'total_possible_used_memory'} = $mycalc{'server_buffers'} + $mycalc{'total_per_thread_buffers'};
$mycalc{'pct_physical_memory'} = int(($mycalc{'total_possible_used_memory'} * 100) / $physical_memory);

# Slow queries
$mycalc{'pct_slow_queries'} = int(($mystat{'Slow_queries'}/$mystat{'Questions'}) * 100);

# Connections
$mycalc{'pct_connections_used'} = int(($mystat{'Max_used_connections'}/$myvar{'max_connections'}) * 100);
$mycalc{'pct_connections_used'} = ($mycalc{'pct_connections_used'} > 100) ? 100 : $mycalc{'pct_connections_used'} ;

# Key buffers
if (mysql_version_ge(4, 1)) {
$mycalc{'pct_key_buffer_used'} = sprintf("%.1f",(1 - (($mystat{'Key_blocks_unused'} * $myvar{'key_cache_block_size'}) / $myvar{'key_buffer_size'})) * 100);
}
if ($mystat{'Key_read_requests'} > 0) {
$mycalc{'pct_keys_from_mem'} = sprintf("%.1f",(100 - (($mystat{'Key_reads'} / $mystat{'Key_read_requests'}) * 100)));
} else {
$mycalc{'pct_keys_from_mem'} = 0;
}
if ($doremote eq 0 and !mysql_version_ge(5)) {
my $size = 0;
$size += (split)[0] for `find $myvar{'datadir'} -name "*.MYI" 2>&1 | xargs du -L $duflags 2>&1`;
$mycalc{'total_myisam_indexes'} = $size;
} elsif (mysql_version_ge(5)) {
$mycalc{'total_myisam_indexes'} = `mysql $mysqllogin -Bse "SELECT IFNULL(SUM(INDEX_LENGTH),0) FROM information_schema.TABLES WHERE TABLE_SCHEMA NOT IN ('information_schema') AND ENGINE = 'MyISAM';"`;
}
if (defined $mycalc{'total_myisam_indexes'} and $mycalc{'total_myisam_indexes'} == 0) {
$mycalc{'total_myisam_indexes'} = "fail";
} elsif (defined $mycalc{'total_myisam_indexes'}) {
chomp($mycalc{'total_myisam_indexes'});
}

# Query cache
if (mysql_version_ge(4)) {
$mycalc{'query_cache_efficiency'} = sprintf("%.1f",($mystat{'Qcache_hits'} / ($mystat{'Com_select'} + $mystat{'Qcache_hits'})) * 100);
if ($myvar{'query_cache_size'}) {
$mycalc{'pct_query_cache_used'} = sprintf("%.1f",100 - ($mystat{'Qcache_free_memory'} / $myvar{'query_cache_size'}) * 100);
}
if ($mystat{'Qcache_lowmem_prunes'} == 0) {
$mycalc{'query_cache_prunes_per_day'} = 0;
} else {
$mycalc{'query_cache_prunes_per_day'} = int($mystat{'Qcache_lowmem_prunes'} / ($mystat{'Uptime'}/86400));
}
}

# Sorting
$mycalc{'total_sorts'} = $mystat{'Sort_scan'} + $mystat{'Sort_range'};
if ($mycalc{'total_sorts'} > 0) {
$mycalc{'pct_temp_sort_table'} = int(($mystat{'Sort_merge_passes'} / $mycalc{'total_sorts'}) * 100);
}

# Joins
$mycalc{'joins_without_indexes'} = $mystat{'Select_range_check'} + $mystat{'Select_full_join'};
$mycalc{'joins_without_indexes_per_day'} = int($mycalc{'joins_without_indexes'} / ($mystat{'Uptime'}/86400));

# Temporary tables
if ($mystat{'Created_tmp_tables'} > 0) {
if ($mystat{'Created_tmp_disk_tables'} > 0) {
$mycalc{'pct_temp_disk'} = int(($mystat{'Created_tmp_disk_tables'} / ($mystat{'Created_tmp_tables'} + $mystat{'Created_tmp_disk_tables'})) * 100);
} else {
$mycalc{'pct_temp_disk'} = 0;
}
}

# Table cache
if ($mystat{'Opened_tables'} > 0) {
$mycalc{'table_cache_hit_rate'} = int($mystat{'Open_tables'}*100/$mystat{'Opened_tables'});
} else {
$mycalc{'table_cache_hit_rate'} = 100;
}

# Open files
if ($myvar{'open_files_limit'} > 0) {
$mycalc{'pct_files_open'} = int($mystat{'Open_files'}*100/$myvar{'open_files_limit'});
}

# Table locks
if ($mystat{'Table_locks_immediate'} > 0) {
if ($mystat{'Table_locks_waited'} == 0) {
$mycalc{'pct_table_locks_immediate'} = 100;
} else {
$mycalc{'pct_table_locks_immediate'} = int($mystat{'Table_locks_immediate'}*100/($mystat{'Table_locks_waited'} + $mystat{'Table_locks_immediate'}));
}
}

# Thread cache
$mycalc{'thread_cache_hit_rate'} = int(100 - (($mystat{'Threads_created'} / $mystat{'Connections'}) * 100));

# Other
if ($mystat{'Connections'} > 0) {
$mycalc{'pct_aborted_connections'} = int(($mystat{'Aborted_connects'}/$mystat{'Connections'}) * 100);
}
if ($mystat{'Questions'} > 0) {
$mycalc{'total_reads'} = $mystat{'Com_select'};
$mycalc{'total_writes'} = $mystat{'Com_delete'} + $mystat{'Com_insert'} + $mystat{'Com_update'} + $mystat{'Com_replace'};
if ($mycalc{'total_reads'} == 0) {
$mycalc{'pct_reads'} = 0;
$mycalc{'pct_writes'} = 100;
} else {
$mycalc{'pct_reads'} = int(($mycalc{'total_reads'}/($mycalc{'total_reads'}+$mycalc{'total_writes'})) * 100);
$mycalc{'pct_writes'} = 100-$mycalc{'pct_reads'};
}
}

# InnoDB
if ($myvar{'have_innodb'} eq "YES") {
$mycalc{'innodb_log_size_pct'} = ($myvar{'innodb_log_file_size'} * 100 / $myvar{'innodb_buffer_pool_size'});
}
}

sub mysql_stats {
print "\n-------- Performance Metrics -------------------------------------------------\n";

# Show uptime, queries per second, connections, traffic stats
my $qps;
if ($mystat{'Uptime'} > 0) { $qps = sprintf("%.3f",$mystat{'Questions'}/$mystat{'Uptime'}); }
if ($mystat{'Uptime'} < 86400) { push(@generalrec,"MySQL started within last 24 hours - recommendations may be inaccurate"); }
infoprint "Up for: ".pretty_uptime($mystat{'Uptime'})." (".hr_num($mystat{'Questions'}).
" q [".hr_num($qps)." qps], ".hr_num($mystat{'Connections'})." conn,".
" TX: ".hr_num($mystat{'Bytes_sent'}).", RX: ".hr_num($mystat{'Bytes_received'}).")\n";
infoprint "Reads / Writes: ".$mycalc{'pct_reads'}."% / ".$mycalc{'pct_writes'}."%\n";

# Memory usage
infoprint "Total buffers: ".hr_bytes($mycalc{'server_buffers'})." global + ".hr_bytes($mycalc{'per_thread_buffers'})." per thread ($myvar{'max_connections'} max threads)\n";
if ($mycalc{'total_possible_used_memory'} > 2*1024*1024*1024 && $arch eq 32) {
badprint "Allocating > 2GB RAM on 32-bit systems can cause system instability\n";
badprint "Maximum possible memory usage: ".hr_bytes($mycalc{'total_possible_used_memory'})." ($mycalc{'pct_physical_memory'}% of installed RAM)\n";
} elsif ($mycalc{'pct_physical_memory'} > 85) {
badprint "Maximum possible memory usage: ".hr_bytes($mycalc{'total_possible_used_memory'})." ($mycalc{'pct_physical_memory'}% of installed RAM)\n";
push(@generalrec,"Reduce your overall MySQL memory footprint for system stability");
} else {
goodprint "Maximum possible memory usage: ".hr_bytes($mycalc{'total_possible_used_memory'})." ($mycalc{'pct_physical_memory'}% of installed RAM)\n";
}

# Slow queries
if ($mycalc{'pct_slow_queries'} > 5) {
badprint "Slow queries: $mycalc{'pct_slow_queries'}% (".hr_num($mystat{'Slow_queries'})."/".hr_num($mystat{'Questions'}).")\n";
} else {
goodprint "Slow queries: $mycalc{'pct_slow_queries'}% (".hr_num($mystat{'Slow_queries'})."/".hr_num($mystat{'Questions'}).")\n";
}
if ($myvar{'long_query_time'} > 10) { push(@adjvars,"long_query_time (<= 10)"); }
if (defined($myvar{'log_slow_queries'})) {
if ($myvar{'log_slow_queries'} eq "OFF") { push(@generalrec,"Enable the slow query log to troubleshoot bad queries"); }
}

# Connections
if ($mycalc{'pct_connections_used'} > 85) {
badprint "Highest connection usage: $mycalc{'pct_connections_used'}% ($mystat{'Max_used_connections'}/$myvar{'max_connections'})\n";
push(@adjvars,"max_connections (> ".$myvar{'max_connections'}.")");
push(@adjvars,"wait_timeout (< ".$myvar{'wait_timeout'}.")","interactive_timeout (< ".$myvar{'interactive_timeout'}.")");
push(@generalrec,"Reduce or eliminate persistent connections to reduce connection usage")
} else {
goodprint "Highest usage of available connections: $mycalc{'pct_connections_used'}% ($mystat{'Max_used_connections'}/$myvar{'max_connections'})\n";
}

# Key buffer
if (!defined($mycalc{'total_myisam_indexes'}) and $doremote == 1) {
push(@generalrec,"Unable to calculate MyISAM indexes on remote MySQL server < 5.0.0");
} elsif ($mycalc{'total_myisam_indexes'} =~ /^fail$/) {
badprint "Cannot calculate MyISAM index size - re-run script as root user\n";
} elsif ($mycalc{'total_myisam_indexes'} == "0") {
badprint "None of your MyISAM tables are indexed - add indexes immediately\n";
} else {
if ($myvar{'key_buffer_size'} < $mycalc{'total_myisam_indexes'} && $mycalc{'pct_keys_from_mem'} < 95) {
badprint "Key buffer size / total MyISAM indexes: ".hr_bytes($myvar{'key_buffer_size'})."/".hr_bytes($mycalc{'total_myisam_indexes'})."\n";
push(@adjvars,"key_buffer_size (> ".hr_bytes($mycalc{'total_myisam_indexes'}).")");
} else {
goodprint "Key buffer size / total MyISAM indexes: ".hr_bytes($myvar{'key_buffer_size'})."/".hr_bytes($mycalc{'total_myisam_indexes'})."\n";
}
if ($mystat{'Key_read_requests'} > 0) {
if ($mycalc{'pct_keys_from_mem'} < 95) {
badprint "Key buffer hit rate: $mycalc{'pct_keys_from_mem'}% (".hr_num($mystat{'Key_read_requests'})." cached / ".hr_num($mystat{'Key_reads'})." reads)\n";
} else {
goodprint "Key buffer hit rate: $mycalc{'pct_keys_from_mem'}% (".hr_num($mystat{'Key_read_requests'})." cached / ".hr_num($mystat{'Key_reads'})." reads)\n";
}
} else {
# No queries have run that would use keys
}
}

# Query cache
if (!mysql_version_ge(4)) {
# MySQL versions < 4.01 don't support query caching
push(@generalrec,"Upgrade MySQL to version 4+ to utilize query caching");
} elsif ($myvar{'query_cache_size'} < 1) {
badprint "Query cache is disabled\n";
push(@adjvars,"query_cache_size (>= 8M)");
} elsif ($mystat{'Com_select'} == 0) {
badprint "Query cache cannot be analyzed - no SELECT statements executed\n";
} else {
if ($mycalc{'query_cache_efficiency'} < 20) {
badprint "Query cache efficiency: $mycalc{'query_cache_efficiency'}% (".hr_num($mystat{'Qcache_hits'})." cached / ".hr_num($mystat{'Qcache_hits'}+$mystat{'Com_select'})." selects)\n";
push(@adjvars,"query_cache_limit (> ".hr_bytes_rnd($myvar{'query_cache_limit'}).", or use smaller result sets)");
} else {
goodprint "Query cache efficiency: $mycalc{'query_cache_efficiency'}% (".hr_num($mystat{'Qcache_hits'})." cached / ".hr_num($mystat{'Qcache_hits'}+$mystat{'Com_select'})." selects)\n";
}
if ($mycalc{'query_cache_prunes_per_day'} > 98) {
badprint "Query cache prunes per day: $mycalc{'query_cache_prunes_per_day'}\n";
if ($myvar{'query_cache_size'} > 128*1024*1024) {
push(@generalrec,"Increasing the query_cache size over 128M may reduce performance");
push(@adjvars,"query_cache_size (> ".hr_bytes_rnd($myvar{'query_cache_size'}).") [see warning above]");
} else {
push(@adjvars,"query_cache_size (> ".hr_bytes_rnd($myvar{'query_cache_size'}).")");
}
} else {
goodprint "Query cache prunes per day: $mycalc{'query_cache_prunes_per_day'}\n";
}
}

# Sorting
if ($mycalc{'total_sorts'} == 0) {
# For the sake of space, we will be quiet here
# No sorts have run yet
} elsif ($mycalc{'pct_temp_sort_table'} > 10) {
badprint "Sorts requiring temporary tables: $mycalc{'pct_temp_sort_table'}% (".hr_num($mystat{'Sort_merge_passes'})." temp sorts / ".hr_num($mycalc{'total_sorts'})." sorts)\n";
push(@adjvars,"sort_buffer_size (> ".hr_bytes_rnd($myvar{'sort_buffer_size'}).")");
push(@adjvars,"read_rnd_buffer_size (> ".hr_bytes_rnd($myvar{'read_rnd_buffer_size'}).")");
} else {
goodprint "Sorts requiring temporary tables: $mycalc{'pct_temp_sort_table'}% (".hr_num($mystat{'Sort_merge_passes'})." temp sorts / ".hr_num($mycalc{'total_sorts'})." sorts)\n";
}

# Joins
if ($mycalc{'joins_without_indexes_per_day'} > 250) {
badprint "Joins performed without indexes: $mycalc{'joins_without_indexes'}\n";
push(@adjvars,"join_buffer_size (> ".hr_bytes($myvar{'join_buffer_size'}).", or always use indexes with joins)");
push(@generalrec,"Adjust your join queries to always utilize indexes");
} else {
# For the sake of space, we will be quiet here
# No joins have run without indexes
}

# Temporary tables
if ($mystat{'Created_tmp_tables'} > 0) {
if ($mycalc{'pct_temp_disk'} > 25 && $mycalc{'max_tmp_table_size'} < 256*1024*1024) {
badprint "Temporary tables created on disk: $mycalc{'pct_temp_disk'}% (".hr_num($mystat{'Created_tmp_disk_tables'})." on disk / ".hr_num($mystat{'Created_tmp_disk_tables'} + $mystat{'Created_tmp_tables'})." total)\n";
push(@adjvars,"tmp_table_size (> ".hr_bytes_rnd($myvar{'tmp_table_size'}).")");
push(@adjvars,"max_heap_table_size (> ".hr_bytes_rnd($myvar{'max_heap_table_size'}).")");
push(@generalrec,"When making adjustments, make tmp_table_size/max_heap_table_size equal");
push(@generalrec,"Reduce your SELECT DISTINCT queries without LIMIT clauses");
} elsif ($mycalc{'pct_temp_disk'} > 25 && $mycalc{'max_tmp_table_size'} >= 256) {
badprint "Temporary tables created on disk: $mycalc{'pct_temp_disk'}% (".hr_num($mystat{'Created_tmp_disk_tables'})." on disk / ".hr_num($mystat{'Created_tmp_disk_tables'} + $mystat{'Created_tmp_tables'})." total)\n";
push(@generalrec,"Temporary table size is already large - reduce result set size");
push(@generalrec,"Reduce your SELECT DISTINCT queries without LIMIT clauses");
} else {
goodprint "Temporary tables created on disk: $mycalc{'pct_temp_disk'}% (".hr_num($mystat{'Created_tmp_disk_tables'})." on disk / ".hr_num($mystat{'Created_tmp_disk_tables'} + $mystat{'Created_tmp_tables'})." total)\n";
}
} else {
# For the sake of space, we will be quiet here
# No temporary tables have been created
}

# Thread cache
if ($myvar{'thread_cache_size'} eq 0) {
badprint "Thread cache is disabled\n";
push(@generalrec,"Set thread_cache_size to 4 as a starting value");
push(@adjvars,"thread_cache_size (start at 4)");
} else {
if ($mycalc{'thread_cache_hit_rate'} <= 50) {
badprint "Thread cache hit rate: $mycalc{'thread_cache_hit_rate'}% (".hr_num($mystat{'Threads_created'})." created / ".hr_num($mystat{'Connections'})." connections)\n";
push(@adjvars,"thread_cache_size (> $myvar{'thread_cache_size'})");
} else {
goodprint "Thread cache hit rate: $mycalc{'thread_cache_hit_rate'}% (".hr_num($mystat{'Threads_created'})." created / ".hr_num($mystat{'Connections'})." connections)\n";
}
}

# Table cache
if ($mystat{'Open_tables'} > 0) {
if ($mycalc{'table_cache_hit_rate'} < 20) {
badprint "Table cache hit rate: $mycalc{'table_cache_hit_rate'}% (".hr_num($mystat{'Open_tables'})." open / ".hr_num($mystat{'Opened_tables'})." opened)\n";
if (mysql_version_ge(5, 1)) {
push(@adjvars,"table_cache (> ".$myvar{'table_open_cache'}.")");
} else {
push(@adjvars,"table_cache (> ".$myvar{'table_cache'}.")");
}
push(@generalrec,"Increase table_cache gradually to avoid file descriptor limits");
} else {
goodprint "Table cache hit rate: $mycalc{'table_cache_hit_rate'}% (".hr_num($mystat{'Open_tables'})." open / ".hr_num($mystat{'Opened_tables'})." opened)\n";
}
}

# Open files
if (defined $mycalc{'pct_files_open'}) {
if ($mycalc{'pct_files_open'} > 85) {
badprint "Open file limit used: $mycalc{'pct_files_open'}% (".hr_num($mystat{'Open_files'})."/".hr_num($myvar{'open_files_limit'}).")\n";
push(@adjvars,"open_files_limit (> ".$myvar{'open_files_limit'}.")");
} else {
goodprint "Open file limit used: $mycalc{'pct_files_open'}% (".hr_num($mystat{'Open_files'})."/".hr_num($myvar{'open_files_limit'}).")\n";
}
}

# Table locks
if (defined $mycalc{'pct_table_locks_immediate'}) {
if ($mycalc{'pct_table_locks_immediate'} < 95) {
badprint "Table locks acquired immediately: $mycalc{'pct_table_locks_immediate'}%\n";
push(@generalrec,"Optimize queries and/or use InnoDB to reduce lock wait");
} else {
goodprint "Table locks acquired immediately: $mycalc{'pct_table_locks_immediate'}% (".hr_num($mystat{'Table_locks_immediate'})." immediate / ".hr_num($mystat{'Table_locks_waited'}+$mystat{'Table_locks_immediate'})." locks)\n";
}
}

# Performance options
if (!mysql_version_ge(4, 1)) {
push(@generalrec,"Upgrade to MySQL 4.1+ to use concurrent MyISAM inserts");
} elsif ($myvar{'concurrent_insert'} eq "OFF") {
push(@generalrec,"Enable concurrent_insert by setting it to 'ON'");
} elsif ($myvar{'concurrent_insert'} eq 0) {
push(@generalrec,"Enable concurrent_insert by setting it to 1");
}
if ($mycalc{'pct_aborted_connections'} > 5) {
badprint "Connections aborted: ".$mycalc{'pct_aborted_connections'}."%\n";
push(@generalrec,"Your applications are not closing MySQL connections properly");
}

# InnoDB
if (defined $myvar{'have_innodb'} && $myvar{'have_innodb'} eq "YES" && defined $enginestats{'InnoDB'}) {
if ($myvar{'innodb_buffer_pool_size'} > $enginestats{'InnoDB'}) {
goodprint "InnoDB data size / buffer pool: ".hr_bytes($enginestats{'InnoDB'})."/".hr_bytes($myvar{'innodb_buffer_pool_size'})."\n";
} else {
badprint "InnoDB data size / buffer pool: ".hr_bytes($enginestats{'InnoDB'})."/".hr_bytes($myvar{'innodb_buffer_pool_size'})."\n";
push(@adjvars,"innodb_buffer_pool_size (>= ".hr_bytes_rnd($enginestats{'InnoDB'}).")");
}
}
}

# Take the two recommendation arrays and display them at the end of the output
sub make_recommendations {
print "\n-------- Recommendations -----------------------------------------------------\n";
if (@generalrec > 0) {
print "General recommendations:\n";
foreach (@generalrec) { print " ".$_."\n"; }
}
if (@adjvars > 0) {
print "Variables to adjust:\n";
if ($mycalc{'pct_physical_memory'} > 90) {
print " *** MySQL's maximum memory usage is dangerously high ***\n".
" *** Add RAM before increasing MySQL buffer variables ***\n";
}
foreach (@adjvars) { print " ".$_."\n"; }
}
if (@generalrec == 0 && @adjvars ==0) {
print "No additional performance recommendations are available.\n"
}
print "\n";
}

# ---------------------------------------------------------------------------
# BEGIN 'MAIN'
# ---------------------------------------------------------------------------
print "\n >> MySQLTuner $tunerversion \n".
" >> Run with '--help' for additional options and output filtering\n";
mysql_setup; # Gotta login first
os_setup; # Set up some OS variables
get_all_vars; # Toss variables/status into hashes
validate_tuner_version; # Check current MySQLTuner version
validate_mysql_version; # Check current MySQL version
check_architecture; # Suggest 64-bit upgrade
check_storage_engines; # Show enabled storage engines
security_recommendations; # Display some security recommendations
calculations; # Calculate everything we need
mysql_stats; # Print the server stats
make_recommendations; # Make recommendations based on stats
# ---------------------------------------------------------------------------
# END 'MAIN'
# ---------------------------------------------------------------------------

# Local variables:
# indent-tabs-mode: t
# cperl-indent-level: 8
# perl-indent-level: 8
# End:

Save the file and give executable permission to the file
# chmod 755 mysqltuner.pl
# ./mysqltuner.pl  OR # perl mysqltuner.pl

Note: This is a pearl script and to excute it copy the above script to a file with extension .pl and run either of the above command. It will shows the security holes in your mysql db server.