d o l l m o n t . n e t » open source http://dollmont.net Open Source Excellence Sun, 03 Jul 2011 07:36:23 +0000 en hourly 1 http://wordpress.org/?v=3.2.1 The perils of bit rot… http://dollmont.net/the-perils-of-bit-rot http://dollmont.net/the-perils-of-bit-rot#comments Fri, 20 Mar 2009 22:11:41 +0000 chris http://dollmont.net/?p=27 Bit rot is a concept familiar to a lot of people. Usually, it refers to the slow degradation of data storage. Magnetic devices, over time, can lose their charge in places that can cause data holes to appear. Lose a few bits from a file and the file can become useless.

But there’s another form of bit rot that just as insidious and can be far more dangerous. It’s the bit rot that comes from keeping old systems on line and in production with no plan for an upgrade path. Let enough time pass and it could become impossible to upgrade the system.

I have a client that has a production system running an older version of Linux. The version of this particular distro is so old that file repositories are no longer maintained and security patches are no longer offered. Furthermore, this particular server is running a commercial piece of software that has been end-of-life’d by the vendor. Not only does the vendor no longer support the software, it’s impossible to get distribution media for the software. If this system were to blow up somehow, the client is basically screwed. We cannot reload the OS because we no longer have the original install media. We cannot reload the application for the same reason. The vendor might offer an upgrade to the software or we could just pay for the package all over again, but there’s no guarantee that the latest version will be backward-compatible with the existing system. Like I said—screwed.

The good news in this case is that we were able to uplift the entire system into a virtual machine. We can now back up the virtual machine image. In a worst case scenario, we can recover from backup and restore the virtual machine to be the same as the current hardware system. The process of uplifting such an old system was not trivial, and we were lucky that we were able to get it done. The client is now “protected” much more than he would have been had he continued down the same path.

Whenever you put a system in place, you need to plan for the eventual upgrade of that system. The reality is that software, and especially operating systems like Linux, matures. You need to plan for that. Distribution choice matters. Any of the Ubuntu LTS distributions are guaranteed to be supported for 5 years. Commercial distributions like RedHat and their Open derivatives like CentOS have long term support options available, too. Using Open Source tools makes the software path more favourable to upgrade.

Don’t let systemic bit rot happen to you…

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