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4.3 How to make your system robust

When you test a new kernel or a new OS, it is important to make sure that your computer can boot even if the new system is unbootable. This is crucial especially if you maintain servers or remote systems. To accomplish this goal, you need to set up two things:

  1. You must maintain a system which is always bootable. For instance, if you test a new kernel, you need to keep a working kernel in a different place. And, it would sometimes be very nice to even have a complete copy of a working system in a different partition or disk.
  2. You must direct GRUB to boot a working system when the new system fails. This is possible with the fallback system in GRUB.

The former requirement is very specific to each OS, so this documentation does not cover that topic. It is better to consult some backup tools.

So let's see the GRUB part. There are two possibilities: one of them is quite simple but not very robust, and the other is a bit complex to set up but probably the best solution to make sure that your system can start as long as GRUB itself is bootable.