Monthly Archives: February 2010

Subnet scanning with Nmap

If you are ever wondering which ip addresses on your network are currently being used, you can use nmap to find out.

For example to scan an entire class C subnet you can use the following command:

‘nmap -v -sP |grep up’

This will produce a list of ip addresses which are currently being used.

You can also use this command to find a list of inactive ip addresses when you are looking to add devices to your network:

‘nmap -v -sP |grep down’

Introduction to Maatkit

Maatkit is a group of perl scripts that provide advanced methods of administration for Mysql.

Here are a few of the more useful things that Maatkit allows you do to:

  1. Monitor MySQL replication delay
  2. Make a MySQL slave server lag behind its master.
  3. Ensuring slaves have the same data as masters
  4. Find duplicate indexes and foreign keys on MySQL tables.
  5. Execute SQL statements and print statistics.
  6. Execute queries on multiple servers and check for differences.

Here is the link to the Maatkit website which provides more details on each of the scripts.  I will be providing some real world examples of Maatkit usage in another post.

Percona patches for mysql 5.1

Percona has recently released some of their performance patches for Mysql 5.1.  Previous to these patches were only available for the 5.0.x codebase.

You can read more about it here. The link also provides from interesting benchmarks as well, pitting these patches vs the standard storage engine setup.

To be clear, these patches work against the built in version of Innodb with comes standard with the Mysql server.

You can xtradb if you wish to use some of the Percona patches that pertain to the Innodb plugin that is offered by Innobase

Streming media server

If you are looking for a way to stream media to either your xbox360 or your ps3 from a linux machine, then I highly recommend that you have a look at this project.  Ps3 Media Server is a java app that you can use to stream all kinds of content to either device.

I have been using it for almost a year now on Ubuntu and it has proven to be  extremely stable.

It also offers ‘on the fly’ transcoding which will allow you to play audio and video formats that might not be natively supported.

Here is the most well documented configuration guide I have come across while looking for tips and tricks.