What is DNS Server

DNS Root Servers

DNS servers communicate with each other using private network protocols. All DNS servers are organized in a hierarchy. At the top level of the hierarchy, so-called root servers store a complete database of Internet domain names and their corresponding IP addresses. The Internet employs 13 root servers that have become somewhat famous for their special role. Maintained by various independent agencies, the servers are aptly named A, B, C and so on up to M. Ten of these servers reside in the United States, one in Japan, one in London, UK and one in Stockholm, Sweden.

 

cpanel backup transfer On Linux Server

CPanel Backup :

Files- > Backup Wizard

Backup

This feature allows you to download a zipped copy of your entire site, or parts of it, to your computer.

The zip file includes the following backed-up items:

  • Home Directory
  • MySQL Databases
  • Email Forwarders Configuration
  • Email Filters Configuration

click on backup option

There will be option Full Backup  And Partial Backup

Full Backup:

You can not Restore Full Backup inside CPanel

Partial Backup

You can take a backup of home directory / Databases and Email

This Backup you can restore inside the CPanel but there are some limitations

you can not transfer Sub Domain and Database Users inside new panel.This we need to crate manually.

 

 

 

 

 

Where and when we can apply MySQL Indexing

Tags

, ,

You can apply Index to the columns that you use for searching, sorting, or grouping, join clauses [not columns you only display as output.]

More About Indexing :

indexes speed up retrievals but slow down inserts and deletes.as well as updates of values in the indexed columns.

Precaution needs to be take while indexing:

The more indexes inside the table ,the more changes need to be made, and the greater the average performance degradation

mysql storge engine [innoDB and MyISAM] practical statistics

Storage Type:

below are the practical statistics to understand the database storage engines and its advantages and disadvantage

i have created the PHP scripts which inserts the 5000 rows inside the mysql table.

——————————————————————————-

in case of INNODB 

we can Insert 130-250 rows at a time only [it might depend on the processor of your server/ computer]

after inserting almost 2000 rows by script [please note for inserting 2000 rows through scripts i have to manipulate script for arranging and inserting them in order]

now i applied Select query on that table , it has taken 0.06 sec to fetch all the record

——————————————————————————–

in case of MyISAM

we can directly insert the 2000-5000 rows inside the table

to select 2000 rows it will take around 0.005 sec

From the above statistics we feel that MyISAM is more better than InnoDB but there is oe major disadvantage in large amount of data………………that we can not apply proper indexing to MyISAM table…………which is very bad scenario.

Continue reading

mail with multiple attachment

// array with filenames to be sent as attachment

$files = array(“file_1.ext”,”file_2.ext”,”file_3.ext”,……);
// email fields: to, from, subject, and so on
$to = “mail@mail.com”;
$from = “mail@mail.com”;
$subject =”My subject”;
$message = “My message”;
$headers = “From: $from”;
// boundary
$semi_rand = md5(time());
$mime_boundary = “==Multipart_Boundary_x{$semi_rand}x”;
// headers for attachment
$headers .= “\nMIME-Version: 1.0\n” . “Content-Type: multipart/mixed;\n” . ” boundary=\”{$mime_boundary}\””;
// multipart boundary
$message = “This is a multi-part message in MIME format.\n\n” . “–{$mime_boundary}\n” . “Content-Type: text/plain; charset=\”iso-8859-1\”\n” . “Content-Transfer-Encoding: 7bit\n\n” . $message . “\n\n”;
$message .= “–{$mime_boundary}\n”;
// preparing attachments
for($x=0;$x<count($files);$x++){
    $file = fopen($files[$x],”rb”);
    $data = fread($file,filesize($files[$x]));
    fclose($file);
    $data = chunk_split(base64_encode($data));
    $message .= “Content-Type: {\”application/octet-stream\”};\n” . ” name=\”$files[$x]\”\n” .
    “Content-Disposition: attachment;\n” . ” filename=\”$files[$x]\”\n” .
    “Content-Transfer-Encoding: base64\n\n” . $data . “\n\n”;
    $message .= “–{$mime_boundary}\n”;
}
// send
$ok = @mail($to, $subject, $message, $headers);
if ($ok) {
    echo “<p>mail sent to $to!</p>”;
} else {
    echo “<p>mail could not be sent!</p>”;
}
?>