11.3. Server Migration and Scalability Issues

With support for a diverse selection of hardware, as well as proven speed and reliability, Linux is up to the challenge of scaling up to meet resource demands as they increase. This can include moving to an SMP (Symmetric Multi Processing) configuration for greater processing needs, RAID levels 0 through 5 (either in software or hardware driven modes), etc.

On occasion, you may feel that your Linux server has outgrown the hardware it is running on, perform a major Linux version upgrade, or perhaps move to a different distribution of Linux. There are, of course, two ways of doing this. Either you will be leaving your server on existing or upgraded hardware (in which case you need simply shut down services, back up your data, perform the required modifications, and then restore data if needed), or in the more radical case, migrate your server to new hardware.

This section will concentrate more on the latter situation, where you will be actually migrating your various services from the old server to a new one. There are, of course, several migration strategies, however this section will attempt to provide some rough guidelines which you can follow in order to ensure your migration effort succeeds with minimal disruption to your users.

Once you are done, make sure everything is working as expected! If not, you can always re-enable any services you disabled on the old server and restart them so that users can continue using it until you resolve the problems on the new one (bear in mind, however, that you'll need to repeat the above steps again if you choose to do that).