Date: Thu, 14 Feb 2008 17:50:51 -0800 From: "Chris H." <chris#@1command.com> To: Kevin Oberman <oberman@es.net> Cc: freebsd-stable@freebsd.org, Gavin Spomer <spomerg@cwu.EDU> Subject: Re: Rebuilding World Problems Message-ID: <20080214175051.l5kg7xfqyocksggs@webmail.1command.com> In-Reply-To: <20080214040243.D78F545017@ptavv.es.net> References: <20080214040243.D78F545017@ptavv.es.net>
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Quoting Kevin Oberman <oberman@es.net>: >> Date: Wed, 13 Feb 2008 13:25:04 -0800 >> From: "Chris H." <chris#@1command.com> >> Sender: owner-freebsd-stable@freebsd.org >> >> Quoting Gavin Spomer <spomerg@cwu.EDU>: >> > 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. :) > > Absolutely not. You are stretching the logic a bit too far on this. I'll > admit I am baffled by why imp added this to UPDATING. > > If you have a valid fstab file, it will have a line (usually the first > non-comment line) that specifies the partition as (1) ufs and (2) rw. As > a result, 'mount -a -t ufs' will remount / as read-write before trying > to mount any other file systems. > > In over a decade of using FreeBSD (since early V3 days), I have never > bothered to specify the explicit remount of /. > >> > >> > 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. :) > > Actually, swap is not enabled in single-user mode. It is enabled very > early in the startup sequence going to multiuser, but, for obvious > reasons, it can't be enabled until dumpon has run. It also starts after > initrandom, geli, gbde, encswap, and ccd, although most people don't > have all of these enabled. > > If you are upgrading a system with limited memory and don't start swap, > you may run out of RAM and the upgrade will freeze. Not good. Even if it > odes not freeze, memory fragmentation could significantly slow progress. > > In most systems the installworld and mergemaster will never touch swap > and the step has no impact, but it never hurts. > >> > >> > 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". :) > > Not at all. Many systems run with a hardware (BIOS) clock set to local > time. Your system will run with this time until ntpd can reset it near > the end of the init sequence. Many files may be created with broken > timestamps during this interval. > > You can easily check by entering the command 'date' after the system > reaches the single-user prompt. If the time printed is correct, there is > no need for the 'adjkerntz -i'. If the time is an hour or more off, it > is needed. If you live in the UK or any other country in the 0 offset > time zone (not many) and it's not summer time, this is not an issue. > >> > >> > 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. > > Sorry, but this is not Linus' doing. for better or worse. He provides a > kernel, not an operating system. Red Hat, Suse, Mandriva, Ubuntu, > Debian, et. al. provide operating systems that use Linus' kernel and > use the name Linux. >> >> 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/. :) > > I, too, have been using BSD for a bit longer than FreeBSD has existed, > having used it while supporting the UC Davis Department of Applied > Sciences back in the 1970s. Not that the CSRG BSD days are relevant to > much of this as the boot-up as well as the rebuild procedures have been > totally re-worked since then (thank goodness). Indeed! :) I'll just summarize here by saying that technically, you are correct on all points. I'm afraid I must admit to "glossing over" all the questions by meerly attempting to make the point that following the "cheat sheet" by executing all the commands would help insure an UNeventful, and successful build/install. In short; while some of the commands were perhaps redundant, no harm would come of making them. :) As to Linux; I guess the only point I was trying to make here was that it isn't reasonable to compare Linux to UNIX, nor is it even reasonable to /call/ Linux UNIX. While not exactly related to building/installing world/kernel. It is related to the kernel, and - in my opinion, ultimately defines the largest difference between the two. That being ld. It is my opinion that the UNIX version - at least where *BSD is concerned, is /vastly/ more efficient, and hence, making the OS more flexible than the Linux families. As to one example; the ability to load both PHP4, and PHP5 as libraries in Apache. In Linux (and others) it is not possible, as there would be symbol crash/collision. Anyway, that doesn't really have anything to do with building/installing world/ kernel, except to the extent that building, and installing the *BSD kernel would be a better choice, which clearly makes *BSD the better choice of OS. :) --Chris H > -- > R. Kevin Oberman, Network Engineer > Energy Sciences Network (ESnet) > Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) > E-mail: oberman@es.net Phone: +1 510 486-8634 > Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751 > -- panic: kernel trap (ignored)
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