Comment 5 for bug 530071

So, for the most part this is all obviously sensible. The installer can and should create partitions with optimal alignment (and I've made that change, pending testing), and it makes complete sense for mkfs.ext4 to complain when you do something that will result in poor performance.

The bit that is a little bit awkward is this: imagine that you take an existing partition which was created before we fixed the partitioner to deal with optimal alignment, and try to overwrite it with a new ext4 filesystem (which may seem to be a perfectly reasonable action to a user unfamiliar with the minutiae of logical sector sizes). mkfs.ext4 will complain in the manner you describe, and there seems to be no straightforward way to force it to proceed anyway (short of 'yes | ...', which I don't think is acceptable!). We should probably implement the same check in the partitioner when we're about to create a new filesystem, but if the user says that they don't want to move the start of the filesystem, what are we to do? Ideally we'd be able to run mkfs.ext4 under the covers with a "yes, I know, just get on with it" option.

Ted, would you be willing to make the alignment warning here overridable using a command-line option?