TuxTraining

Linux has excellent software-based RAID built into the kernel. Unfortunately information on configuring and maintaining it is sparse. Back in 2003, O’Reilly published Managing RAID on Linux and that book is still mostly up to date, but finding clear instructions on the web for setting up RAID has become a chore.

Here is how to install Ubuntu Server with software RAID 1 (disk mirroring). This guide is for Ubuntu Server 6.06 LTS, but the procedure should be nearly the same for newer versions of Ubuntu and even Debian. We’ve also included a few other tips, like how to ensure you can still boot your server when the first drive fails and how to rebuild when replacing a failed drive.

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Here are a few tricks for APT, the Advanced Packaging Tool used on Debian and Debian-based distributions like Ubuntu.
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Cacti is a web based PHP/MySql graphing solution using the RRDtool engine. Classically, it can graph network bandwidthes with SNMP. But in fact, a lot of different graphs can be done with snmp, shell or perl scripts.

Cacti’s strength lies in the fact that it can be installed and used incredibly easily. You don’t need to be a guru or spend tons of hours on the tool to configure it. Even a beginner can use it very quickly. On the very active Cacti forum, you can share “Cacti templates” with other users which can can save you a lot of time. You can very easily add plugins to the Cacti too enabling the possiblility to integrate other free tools like ntop or php weathermap. In our opinion, this is by far the best RRDtool frontend.
For details about how to use Cacti, see the very good Cacti Manual.

RRDtool is a program developed by the Swiss Tobi Oeticker who was already the creator of the famous MRTG. RRDtool is developed using the “C” programming language and it stores the collected data on “.rrd” files.

The number of records in a “.rrd” file never increases, meaning that old records are frequently removed. This implies that one obtains precise figures for recently logged data, whereas figures based on very old data are mean value approximations. By default, you can have daily, weekly, monthy and yearly graphs.

Some of the advantages of RRDtool over MRTG are the following:

- it is much quicker..
- it can use negative values.
- it can use more than one data source in a graph.
- the generated graphes are very customizable.
- it can be used by a wide variety of front-ends such as Cacti.
- the RRDtool records stored in .rrd files keep the same size and do not increase.

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