Rebuilding World Problems

[Gavin Spomer]

>>>> "Chris H." <chris#@1command.com> 02/12/08 4:34 PM >>>
>Quoting Gavin Spomer <spomerg at cwu.EDU>:
>> First, let me note that step one in rebuilding world should be "cd 
>> /usr/src", not "make buildworld". I guess I was supposed to know that 
>> for some reason. Having said that, I figured I would also have to be 
>> in /usr/src for the "make installworld" step. But I couldn't do that! 
>> Why? I could cd to /usr, but not /usr/src!
>> So, I decided to go ahead and try the "mergemaster -p" step. I was 
>> given an error that was something like "cannot find mergemaster". So 
>> I thought that maybe in single user mode my $PATH isn't set, so I 
>> thought about entering "/sbin/mergemaster -p", but I didn't know if 
>> that was the path or not and I chickened out. :( Maybe the fact that 
>> I hit Return to choose /bin/sh while going into single user mode 
>> instead of my preferred bash had something to do with it?
>> Here's a slightly dumb question: when I get this all figured out, do 
>> I have to start all over from "make buildworld" or can I just 
>> continue with booting in single user mode and "mergemaster -p"? I'm 
>> guessing I can just continue, but I thought it was important to ask.
>> Here's a little more intelligent question or two. ;) Is there a way 
>> to do this while logged in via ssh? I don't mind making the trip to 
>> our computer room so I can select #4 at the FreeBSD prompt, but it's 
>> not all that convenient. Also, how long (in general) do the steps 
>> "mergemaster -p" through the final reboot take? I am running FreeBSD 
>> on a test server, but if I were to use it for my production servers 
>> (which I am considering), the down-time of being in single user mode 
>> would be a concern.
>> Thanks to everyone who takes the time to read this. :)
>
>Greetings Gavin,
>Yes, you're quite correct on all accounts. The doc's are a bit terse
>in these areas. Which, as I read your email, reminds me why I _should_
>send-pr a patch with some additional info in these areas. I guess I'm
>like so many others - once I figured it all out, I got so involved
>with it all, I completely forgot there was some issues with the docs.
>NOTE: I'm not the author of the documentation. :)
>OK I'm going to give you a "cheat sheet" that I hope you'll find
>helpful in the future - be aware, this is NOT an excuse to ignore
>the /usr/src/UPDATING file, as THAT document will QUITE likely
>contain more timely information regarding little, but important
>changes, that can make all the difference.
>That said, here goes:
>--------------------------------------------------------
>* On an initial install ALWAYS buildworld BEFORE buildkernel
>* Unless having troubles building a kernel, it is usually
>   best to ensure /etc/make.conf is empty
>* If REbuilding world/kernel it is usually a good idea to
>   perform the following:
>cd /usr/obj
>chflags -R noschg *
>rm -rf *
>(see chflags(1) for more information)
>--------------------------------------------------------
>OK here we go:
>cd /usr/src/sys/<ARCH>/conf
>cp ./GENERIC ./YOUR_CHOSEN_NAME
>edit ./YOUR_CHOSEN_NAME and adjust as necessary
>cd /usr/src
>make buildworld
>* * * * OPTIONAL * * * *
>NOTE: SINGLE CPU:
>make -j4 buildworld
>NOTE: MULTI CPU:
>make -j(6 through 10) buildworld
>* * * * * * * * * * * *
>make buildkernel KERNCONF=YOUR_KERNEL_HERE
>make installkernel KERNCONF=YOUR_KERNEL_HERE
>reboot (in single user mode)
>fsck -p (optional, but a good idea)
>mount -u /
>mount -a -t ufs
>swapon -a (most cases; optional)
>cd /usr/src
>mergemaster -p
>make installworld
>mergemaster
>reboot
>That was simply a QUICK cheat sheet, and does not
>replace good research. But I hope it helps. :)
>--Chris

Thanks, this was very helpful. First of all I would just like to admit that I only gave /usr/src/UPDATING a quick glance. Shame on me; it might have solved most (if not all) of my problem if I had read more thoroughly.

Surprisingly I grokked most of your cheatsheet and looked at a few man pages to figure out most of the rest. Haven't tried it all yet. I was wondering about the "mount -u /". Is it really necessary to mount the root partition prior to mounting all of them in the next step?

I don't really understand the "swapon -a". When is it necessary and when is it not?

Also, UPDATING has "adjkerntz -i" just before "mergemaster -p". I looked at the man page for adjkerntz and am still uncertain if I need to do this. I run an ntpd client, if that makes any difference.

I think the documentation is an excellent reference for people who already, moderately know FreeBSD. I am not even a true newbie as I have a CS degree and have been a Linux admin for 2 years. Even so I often have a hard time with the complexity of FreeBSD. I recognize the value of understanding the fine-grain "nuts and bolts" of a system, but even so I wonder if FreeBSD over-complicates some things?

- Gavin