Setting up Linux softRAID10 so it can boot after a drive failure

I see you've already figured out how to accomplish this from a high level interface, but for the sake of anybody else who would like to learn how to configure software RAID10, I'll link to a fantastic article that goes into great depth on how to accomplish this. Rather than copy the article verbatim, I'll link to it instead. I used this article as a guide to set up RAID 10 for a file server; it also explains how to configure GRUB to successfully boot after a disk failure.

I usually don`t do this with grub. The problem - which is not addressed in the referenced article is:

If you loose sda (=hd0) your previous sdb (=hd1) will become sda (=hd0) which confuses grub: It was installed to sdb/hd1.

I use dd from one partition to the other to copy the whole boot-partition (including grub-setup).

And don`t forget to set up your bios so it will continue to boot in case of a drive failure. ;-)