Shell Tips !

With Ganglia, graphing a large number of servers has never been so easy… Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and Grids. Ganglia let you create any kind of module in C/C++ or Python. You can also use the command line tool Gmetric and then the scripting language of your choice. The problem with Gmetrics is that you can’t keep your data organized by group and it’s getting harder to poll values in an efficient way. Few months ago I needed to monitor some JMX values returned by a Java daemon.

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My previous post was made a long time ago, so here is a draft that I finally decide to post. Let’s see how to secure some of your data with an encrypted block device using losetup and dd.

Steps will be :

1. Create an image with dd
2. Build a new device using the image with an encrypt algorythm by using losetup
3. Format the device using mkfs.ext3
4. Mount the device and start using it !

Of course, when you have mounted the device, your data are readable to anyone who have access to the mounted directory.

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Here is a quick post about a cheap SAN and secure backup architecture solution for small-sized platform (5/10 servers). In this study case we will see how to use Network Block Devices (nbd) and soft-raid with mdadm. I design it for my personal web platform which is a small one. Last day, I was missing of free space on my backup server and I was angry by the idea to rent a most expensive server to store my backup while I had lot of unused space on my other servers.

1. Initial platform
2. New platform
3. How to do it ?

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