Rebuilding World Problems

Wed Feb 13 21:25:16 UTC 2008

Quoting Gavin Spomer <spomerg at cwu.EDU>:

>>>>> "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?

Absolutely. Think about it for a momment. Given that EVERYTHING
(save swap) is mounted off of root ( / ). So it becomes quite
impossible to mount /usr/ if / hasn't already been mounted. In
other words; if / hasn't been mounted it doesn't exist for usr/
to mount from it. :)

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

As a rule, it is already available after boot. So executing swapon -a
is often considered overkill. /But/ absolutely no harm will come of
doing it, and it /may/ be necessary. So this just insures you have
an "event free" journey. :)

>
> 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.

Again, just a precaution. Think "safe", or "event free". :)

>
> 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?

This is the "UNIX way". It breaks everything into small bits of
useful stuff. There-by providing the "nuts & bolts" to build, or
accomplish almost /anything/ with little, or no effort. Linux kind
of "missed the boat" on this one. But even Linus T. indicates that
Linux is not UNIX. I'd have to say, it's more a "feels like UNIX"
than anything else.

To sum things up; given that I've been using BSD since long before
FreeBSD even existed. I can't imagine how anyone would consider
using anything /but/ *BSD. It is /infinitely/ flexible, which only
adds to it's power. While - as you mentioned, it seems complicated
to a new user. One must remember, after all, that it is a /server/
and perhaps, not best suited to an average "desktop" user. But, if
given the time, will become your best friend - /really/. :)

Best wishes to you.

--Chris H.

>
> - Gavin
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-- 
panic: kernel trap (ignored)