On 06/19/10 16:17, Jeff Ross wrote: > Thanks for the reality check Nick! The last thing I want is another > point of failure--I obviously wan't thinking this through.
Easy trap to get into. :) > Interesting about the /altroot partition. I hadn't yet edited > /etc/fstab to change the altroot line but I sure did not know that > the system should automatically boot from /altroot if the root partition > has gone missing--I thought that took human intervention. In your designs and planning, one should not assume their computer will automatically boot from the second drive that an /altroot is on, but ideally, you should be able to make it so the /altroot drive CAN boot, and then it should Just Work, once you get the drive in the right place to boot. For some kinds of failure on some combinations of hardware, things work out without human intervention (and sometimes there are adjustments you can make to improve your chances), but don't plan on it. The usual manual intervention one should assume include removing the bad disk and reset the drive/hardware/whatever to what the remaining drive needs to be to boot. This may be moving the drive to a primary channel, moving from "slave" to "master" (or "only"), or sticking the drive in slot0, or... In your case, your computer WAS trying to boot from that "second" disk, so it should have succeeded. Probably good that it didn't, as if it had, you MIGHT not have noticed it was doing things funny. (I spent a long time thinking there was some issue with booting from your altroot accidentally, but either the last couple day's activities left me too tired to think then or I'm too tired to think now, but I can't think of a big problem caused by a successful boot from your altroot as you were trying to do here.) IF you have an altroot carefully and properly set up, the second disk CAN be directly bootable. You need the altroot to be an 'a' partition on the second drive, on fdisk platforms, you need a valid MBR boot code and the OpenBSD partition flagged active. Testing is good, easy to mess up a step (active partition is my favorite). Nick.
