RE: FreeBSD boot menu is missing

Mirroring the entire slice is far simpler. If you mirror individual
partitions, you have to label them *before* you newfs them.

What we're really trying to accomplish is an automated install via a PXE boot server. Unfortunately gmirror isn't available in mfsroot at the point the file systems need to be set up. So what we've ended up doing is doing is what amounts to a bootstrap install on the first disk, and then after the installCommit is done, gmirror is available and we have a post install script that runs gmirror on the other drives. Then the script copies the OS slice over to the gmirrored fs, reboots to this mirrored system, and finally adds the original disk to the mirror. It's fully automated and gives us a mirrored OS slice across four drives, and we even handle drives of different sizes.

I would mirror the whole drive, though

We can't do that. The data on the non-mirrored portion is different on each drive and we don't want it mirrored.

- and I would use ZFS, with which
you can easily transition to larger drives (just replace them one by one
and resilver in between - you can even do it online if your disks are
hot-swappable)

FreeBSD doesn't handle hot swap very well we've discovered, not unless you are using a RAID based backplane and drives. We cannot use RAID in our application, and don't in fact want to. We're still trying to figure out how to deal with drive removal in a live non-RAIDed system.

We plan to move to ZFS but we are too close to a release cycle to make the move now (QA would have to run through weeks of testing). ZFS will happen, though, sooner or later.

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