Updating a ZFS on Root installation in FreeBSD 8
Ever since ZFS became production ready on FreeBSD 8 (and backported to 7), I've been itching to switch to using it and getting rid of UFS. For one, UFS is OLD. It was first used in 4.2BSD if that gives any indication. The most salient problem with UFS is the lack of real journaling. True, you have the soft-updates feature, but soft-updates are an alternative to journaling. This may not be a problem for users with older hardware and smaller hard disks, but with today's multi-terabyte drives, a power failure or system crash can lead to painfully long waits as fsck verifies the consistency of your file system.
To that end, I followed this handy guide to installing a FreeBSD system on a pure ZFS-only setup. Note that you'll end up with a system with no traces of UFS whatsoever, meaning you have to use the ZFS bootloader and can't dual boot anymore. If that's not to your liking, have a look at the index of ZFS on root guides. If you need to dual boot, you'll want to follow one of the MBR guides. For my needs, if I find myself needing to boot to another operating system, I simply hit F12 when my system is performing a POST test and choose a different drive to boot to. It's simple and separates your operating systems so they don't affect one another. Another alternative is to use virtualization if your needs aren't too demanding.
One thing none of the ZFS on root guides show you is also one of the most important: how to update and rebuild your system! If you're a developer you probably already know how to do this, but for the rest of us, it's important to know how to properly update your system when needed.
To begin, you'll want to sync your source tree. Instructions for that are located in the handbook, but it really boils down to using csup to synchronize source from a cvsup server to your local machine. If you do anything that requires building a kernel module, you're probably familiar with this. With your source tree synchronized to your desired version of FreeBSD, you can follow the the handbook guide to rebuilding world.
Once you have installed the kernel, reboot into single user mode as the guide tells you. Issue the "mount" command. You'll notice that no filesystems are mounted except for devfs and the root ZFS filesystem you marked as legacy. The handbook tells you to use "mount -a -t ufs" but obviously this won't work since we have banished UFS from our FreeBSD box. To mount all the ZFS mountpoints you have, simply use "zfs mount -a". This should mount everything except for / (root) as read-write. To enable a writable file system root, use "mount -uw /" and then "mount -a" to mount anything else. The "-uw" option unsets any mount options and then sets the write bit so you can write to that mount point. At this point you should be able to use mergmaster and installworld to finish rebuilding your system. One important task you must do before rebooting into your updated system is to install updated boot code. This is done with the following command after installing the new world: "gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 disk" where disk is the name of the drive you installed to (usually ad0). With this, you should have an updated system with ZFS as your file system!
Enjoy!
FreeBSD 7 on a Thinkpad T40 update
Not too long ago I wrote a how-to article on how to get FreeBSD 7.0 working on my IBM Thinkpad T40. Among other things, I omitted a section on getting proper video drivers working. The graphics chip is an ATI RV250 (Mobility 9000). This means the driver you should use is the 'radeon' driver. Use 'pciconf -lv |grep ATI' to see which chip you've got. After toiling a bit with it, I figured out how to get the Open Source ATI drivers working.
Because I want to generally keep my systems pretty current, I recently installed FreeBSD 7.1 on my T40. It's important to know that the FreeBSD project generally breaks up development into three separate releases, namely CURRENT, STABLE, and RELEASE, in order of most bleeding edge to most stable. After building Xorg 1.6.0, I tried to start an X session just to see if I would get the ugly TWM desktop. To my surprise I got just a black screen but that was it. Even more surprising was that the usual "three finger salute" (ctrl + alt + backspace) didn't kill my X session. I then hit 'alt + F2' to log into another vty and manually kill off X. Here's where the fun began. It killed more than X; it locked my entire machine up. I continued futzing with my xorg.conf, kernel modules, and locking my system up for a good hour. I then threw in the towel and wound up asking a friend who's a FreeBSD developer WTF was going on. I learned a few interesting facts:
- The DRM code in 7.1 was more than 2 years old
- It is not necessary to manually load or pre-load any kernel modules for video
- X.org should work well with ATI graphics cards (but the amd64 release may not work) since the ATI driver model has had substantial structural changes to it.
On the first point, there's two ways around the old code: Either download/burn/install the FreeBSD 7.2 release candidate or rebuild world. Since I'm a glutton for punishment, I decided to rebuild world. It's not actually that hard, just time consuming. Use the 'csup' utility to grab the entire CVS source tree from your nearest csup server and follow the directions listed here to rebuild your system using the RELENG_7 tree.
The second point is easy enough. There's no need to add anything to your /boot/loader.conf file in order to get X working. X.org will load any necessary kernel modules when you type 'startx'. As an interesting aside, I actually locked my system up when attempting the unload the radeon.ko kernel module when I had learned that preloading isn't necessary. Doh!
Once you've rebuilt your system and are running 7.2-STABLE, it probably wouldn't be a bad idea to rebuild your installed ports. This isn't necessary per se since X.org should work without even building a config file, but it is a good step, just to make sure everything is up to date. I use the portupgrade utility located in /usr/ports/ports-mgmt/ with the following: portupgrade -aRr. That should upgrade all outdated ports recursively as well as recursively rebuilding dependencies.
I'll expand on the last point a bit. ATI has been much more generous with contributing documentation to the Open Source community than Nvidia. In fact, Nvidia hasn't contributed anything other than a proprietary driver for Linux and FreeBSD, though there's a project called Nouveau which aims to build an Open Source Nvidia driver. Because of this, FreeBSD has an Open Source ATI driver (/usr/ports/x11-drivers/xf86-video-radeonhd and usr/ports/x11-drivers/xf86-video-ati) and using the old proprietary fglrx driver is no longer necessary. There's one hiccup to this though. The driver has to be re-worked every time a new ATI chip comes out. To solve this, ATI is moving towards the same unified driver model Nvidia has used for years and taking it a step further. They now have an Open Source BIOS abstraction layer called ATOMBios. The idea is to make it easier to more rapidly deploy drivers for new graphics cards. Read all about that in this article. Bravo ATI!
By the time you finish reading this, your ports should be up to date and you should be able to use hardware accelerated ATI drivers on your Thinkpad. I'm running XFCE4 on my Thinkpad and it's causing me to reevaluate the old "FreeBSD vs. Linux" question. Maybe I'll spend a little more time working on the other parts that I overlooked in my article.
Enjoy!