Installing FreeBSD on a USB stick, episode II

Posted by Ceri Davies Thu, 13 Apr 2006 21:37:00 GMT

I previously wrote about putting a 6.1-BETA4 FreeBSD installation on a USB stick. Since the bugs that were in the 6.1-BETA4 installation have been fixed, plus to get 6.1-RC1 tested, here are updated instructions (which should work with 6.1-RELEASE as well).

These instructions result in a downloadable image suitable for dding direct to a USB stick of 512MB or larger.

arved pointed out that it’s good to minimize the amount of writes done to USB sticks (and flash memory in general), and I’ve got some pointers in these instructions, but I haven’t really looked at this point.

If you are looking to install FreeBSD from a USB stick, you should check out Dario Freni’s script.

Note

I assume that, like me, you don't have any SCSI disks and so your USB stick will show up on da0, at least while you're preparing it; we're using GEOM disk labels in the image so we don't care so much where the disk appears in the device tree. I'm also assuming that you don't care much for the data on your USB stick.

The installation

You'll need to grab the disc1 ISO — get the latest one.

• Mount that ISO on /dist:

     # mkdir -p /dist
     # mdconfig -a -f /a/FreeBSD/6.1-RC1-i386-disc1.iso
     md1
     # mount -t cd9660 /dev/md1 /dist

• Insert the stick. They come preformatted with a FAT32 partition on, so we'll need to throw a BSD slice label on there — this command will destroy all existing slices. If you get a warning regarding "Geom not found", don't worry.:

  # fdisk -BI /dev/da0
  

• We need a disk label:

  # bsdlabel -B -w da0s1
  

• and a filesystem, which we'll mount on /mnt. In order to reduce the number of writes to the USB pen, and as common practice, we use the -U flag to enable soft updates. Additionally, so that we can find the filesystem easily no matter where the USB pen appears in the device tree, we will label the filesystem as FreeBSDonUSB:

  # newfs -U -L FreeBSDonUSB /dev/da0s1a
  /dev/da0s1a: 481.0MB (985040 sectors) block size 16384, fragment size 2048
          using 4 cylinder groups of 120.25MB, 7696 blks, 15424 inodes.
          with soft updates
  super-block backups (for fsck -b #) at:
   160, 246432, 492704, 738976
  # mount /dev/da0s1a /mnt
  

• Now to do an install the blindingly easy way:

  # cd /dist/6.1-RC1/base
  # DESTDIR=/mnt ./install.sh 
  You are about to extract the base distribution into /mnt - are you SURE
  you want to do this over your installed system (y/n)? y
  

• With 6.1, we are providing both uniprocessor and SMP kernels on the CD. sysinstall will install the correct one depending on your hardware configuration, but we need to decide. It's probably OK to just use the SMP one, but I have no multiprocessor machines, so will use the UP kernel. If you want the SMP kernel, just specify smp where I have generic below:

  # cd /dist/6.1-RC1/kernels
  # DESTDIR=/mnt ./install.sh generic
  # rmdir /mnt/boot/kernel
  # mv /mnt/boot/GENERIC /mnt/boot/kernel
  

• Install the boot manager. We use the noupdate option to prevent boot0 writing itself back to disk every boot:

  # boot0cfg -v -B -o noupdate da0
  #   flag     start chs   type       end chs       offset         size
  1   0x80      0:  1: 1   0xa5    480: 63:32           32       985056
  version=1.0  drive=0x80  mask=0xf  ticks=182
  options=packet,noupdate,nosetdrv
  default_selection=F1 (Slice 1)
  

• Create an fstab(5) file on the USB stick. Here's a simple one that puts the logs on to memory storage (to try to minimize writes). We also null mount /var/tmp on /tmp, which makes it non-persistent:

  # Device                Mountpoint      FStype  Options         Dump    Pass#
  /dev/ufs/FreeBSDonUSB   /               ufs     rw,noatime      1       1
  md                      /tmp            mfs     rw,-s16M,nosuid,noatime 0       0
  md                      /var/run        mfs     rw,-s4M,nosuid,noatime  0       0
  md                      /var/log        mfs     rw,-s16M,nosuid,noatime 0       0
  /dev/acd0               /cdrom          cd9660  ro,noauto,nosuid        0       0
  /proc                   /proc           procfs  rw,noauto       0       0
  /tmp                    /var/tmp        nullfs  rw              0       0
  

• Since we're using the UFS label to define the root filesystem, we must force the GEOM label class to be loaded early:

  # cat >> /mnt/boot/loader.conf << EOF
  geom_label_load="YES"
  EOF
  

• vi(1) likes to have a /var/tmp/vi.recover around, so we ensure that it exists on boot. Pull down this example script and install it:

  # mkdir -p /mnt/usr/local/etc/rc.d/
  # cd /mnt/usr/local/etc/rc.d/
  # fetch http://people.freebsd.org/~ceri/FreeBSDonUSB/scripts/mkvirecover
  # chmod 555 mkvirecover
  

• In order for commands that use wtmp(5) to work correctly with /var/log on a memory disk, we need to tell newsyslog(8) that it is OK to create an empty /var/log/wtmp. Edit /mnt/etc/newsyslog.conf and add C to the /var/log/wtmp line:

  /var/log/wtmp                          644  3     *    @01T05 BC
  

• Set the interfaces to configure themselves over DHCP. I exclude plip0 and fwe0 since they are practically never connected to a DHCP server, but are reasonably common:

  # cat >> /etc/rc.conf << EOF
  ifconfig_DEFAULT="DHCP"
  ifconfig_fwe0="NOAUTO"
  ifconfig_plip0="NOAUTO"
  EOF
  

• Again, to reduce the number of writes to the USB key, we will pregenerate a locate database and then turn off the weekly update:

  # chroot /mnt /bin/sh
  # mount_devfs devfs /dev
  # /etc/periodic/weekly/310.locate
  
  
  Rebuilding locate database:
  # cat >> /etc/periodic.conf << EOF
  weekly_locate_enable="NO"
  weekly_whatis_enable="NO"
  EOF
  

• Install any packages you might want, and set a root password:

  # chroot /mnt /bin/sh
  # passwd root
  # pkg_add -r lsof rsync unzip zsh kde...
  

That's it for now.