Think long and hard prior to scheduling linux migrations (for example, upgrading hardware, changing databases, changing web servers, etc). You must understand that planning this type of move includes many more steps than a comparable move for systems built on the Microsoft® Windows® platform.
I am in the process of upgrading hardware for two of my linux servers (both machines running Novell SuSE, versions 10.0 and 9.3) to Intel® Core Duo® hardware, complete with SATA drives and, for one machine, a GForce 7600 graphics card with an NVidia chipset. The upgrades have not been finished. I have hit lots of bumps, as follows:
- The SuSE YaST installation program will not run (out of the box) on the hardware platform. I am working on a fix with SuSE, but why should I need a fix?
- I had to remove the GeForce card. SuSE has problems with the NVidia chip set so, to minimize issues, I removed the card rather than attempt the total install with the card in the motherboard
- Despite using the "tried and true" disk utility application "DD" to image the drive prior to migration, I neglected to open the image prior to the migration and, murphy's law being what it is, the image failed to open properly after the fact. Fortunately, I have the physical disk as well as archives of the critical files.
- Had my schedule required static page production (check out bestplainwebpages.com for further info on what I do) I would have lost 4 production days this week. Fortunately, I am doing much more with scripts this week.
- I have been without my MySQL database for 4 business days awaiting completion of the migration
- I spent 3.5 man days on this "cost" project with no billable result
Given the above, it makes much more sense to design linux systems migrations from the ground up prior to embarking on same. The modus operandi must include
- Verifying that the shrink wrap version of the Linux Distribution of Choice works with the intended hardware out of the box
- Creating all images and ensuring quality by successfully opening all images on fall back hardware that will be available, post migration, should there be problems with the new hardware
- Restricting the timeframe for the migration to after hours
Images are critically important in a Linux environment as, via an image, one has the best shot at preserving file permissions along with data and, thereby, ensuring that stuff works post migration. As well, if any applications have been compiled, imaging the applications within the disk context (complete with all file dependencies in place) is dramatically easier than recreating the dependencies, permissions, etc. after the fact.
© Mike Blonder, 2007, All Rights Reserved