FreeBSD root on ZFS
How to install FreeBSD on a ZFS system 'root' partition
Yarema <yds@CoolRat.org>
Written: 2007-12-20, Last Modified: 2007-12-24
Version: 0.1

Problem

ZFS — the breakthrough file system in FreeBSD 7 (ported from Sun's Solaris 10 Operating System) delivers virtually unlimited capacity, provable data integrity, and near-zero administration. However FreeBSD's sysinstall(8) does not yet support installing the system onto anything more exotic than a commonly used UFS partition scheme. Furthermore FreeBSD's boot loader(8) cannot yet load the kernel and modules from ZFS.

Solutions

Install FreeBSD onto a bootable USB flash drive along with a copy of the zfsboot script on it. Boot from the USB flash drive and run the zfsboot script. This usbinstall script can be used to prepare the bootable USB drive: 

#!/bin/sh
#
# HOWTO/script to create a USB mounted bootable "root" install for
# bootstrapping a ZFS-on-root and the like.
#
# -- Yarema 

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
program=`basename $0`

if [ -f "$0.rc" ];then
  . "$0.rc"
fi

: ${KMEMSIZE:="512M"}
: ${RELEASE:="7.0-RELEASE"}
: ${DESTDIR:="/media"}

if [ $# -lt 1 ]; then
  echo "Usage:	${program}  "
  echo "	where  is the path to the distribution"
  echo "	files, usually an .iso mounted on /dist"
  echo "	and  is usually da0"
  exit 1
fi

dist="$1"
vdev="$2"

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
ask() {
  local question default answer
  question=$1
  default=$2
  read -p "${question} [${default}]? " answer
  if [ -z "${answer}" ]; then
    answer=${default}
  fi
  echo ${answer}
}

yesno() {
  local question default answer
  question=$1
  default=$2
  while :; do
    answer=$(ask "${question}" "${default}")
    case "${answer}" in
    [Yy]*)	return 0;;
    [Nn]*)	return 1;;
    esac
    echo "Please answer yes or no."
  done
}

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
if yesno "Create one slice covering the entire ${vdev}" n; then
  dd if=/dev/zero of=/dev/${vdev} bs=512 count=79
  fdisk -BIv /dev/${vdev}
fi

if yesno "Initialize the BSD label" y; then
  bsdlabel -wB /dev/${vdev}s1
fi

bsdlabel /dev/${vdev}s1
while yesno "(Re)Edit the BSD label" n; do
  bsdlabel -e /dev/${vdev}s1
  bsdlabel /dev/${vdev}s1
done

newfs -U /dev/${vdev}s1a
[ -d ${DESTDIR} ] || mkdir -p ${DESTDIR}
mount /dev/${vdev}s1a ${DESTDIR}

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
: ${dists:="base games manpages info dict"}
for i in ${dists}; do
  echo "  Extracting the ${i} distribution into ${DESTDIR}..."
  cat ${dist}/${RELEASE}/${i}/${i}.??		| tar --unlink -xpzf - -C ${DESTDIR}
done

echo "  Extracting the GENERIC kernel into ${DESTDIR}/boot/"
cat ${dist}/${RELEASE}/kernels/generic.??	| tar --unlink -xpzf - -C ${DESTDIR}/boot && ln -f ${DESTDIR}/boot/GENERIC/* ${DESTDIR}/boot/kernel/

echo "  Copying ${dist}/${RELEASE}/ to ${DESTDIR}..."
tar cf - ${dist}/${RELEASE}/*	| tar --unlink -xpf - -C ${DESTDIR}

# Mounting /var on tmpfs will work for both tmp directories
# by creating a softlink from /tmp to /var/tmp
rm -rf ${DESTDIR}/tmp
ln -sf var/tmp ${DESTDIR}/tmp

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
if [ -f $0.local ];then
  . $0.local
fi

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
echo "vm.kmem_size=\"${KMEMSIZE}\"		# Sets the size of kernel memory (bytes)" >> ${DESTDIR}/boot/loader.conf.local
echo "vm.kmem_size_max=\"${KMEMSIZE}\"		# used by in-kernel malloc(9)" >> ${DESTDIR}/boot/loader.conf.local
echo "nullfs_load=\"YES\"		# Null filesystem" >> ${DESTDIR}/boot/loader.conf.local
echo "zfs_load=\"YES\"			# ZFS" >> ${DESTDIR}/boot/loader.conf.local
echo "geom_eli_load=\"YES\"		# Disk encryption driver (see geli(8))" >> ${DESTDIR}/boot/loader.conf.local
echo "geom_mirror_load=\"YES\"		# RAID1 disk driver (see gmirror(8))" >> ${DESTDIR}/boot/loader.conf.local
${EDITOR:-"vi"} ${DESTDIR}/boot/loader.conf.local

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
echo "# Device		Mountpoint	FStype	Options			Dump	Pass#" > ${DESTDIR}/etc/fstab
echo "/dev/${vdev}s1a		/		ufs	rw,noatime		0	0" >> ${DESTDIR}/etc/fstab
echo "tmpfs			/var		tmpfs	rw,nosuid		0	0" >> ${DESTDIR}/etc/fstab
echo "proc			/proc		procfs	rw			0	0" >> ${DESTDIR}/etc/fstab
echo "# Device		Mountpoint	FStype	Options			Dump	Pass#" >> ${DESTDIR}/etc/fstab
echo "/dev/acd0		/cdrom		cd9660	ro,nodev,noauto,nosuid	0	0" >> ${DESTDIR}/etc/fstab
echo "/dev/fd0		/media/fd	ufs	rw,nodev,noauto,nosuid	0	0" >> ${DESTDIR}/etc/fstab
echo "/dev/fd0		/media/floppy	msdosfs	rw,nodev,noauto,nosuid	0	0" >> ${DESTDIR}/etc/fstab
${EDITOR:-"vi"} ${DESTDIR}/etc/fstab

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
umount /dev/${vdev}s1a

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
# EOF

Implementation

The zfsboot script presented here will create the regular bootable 'a' partition, but configure it as RAID-1 using gmirror(8). This approach provides the possibility to directly boot from any of the drives by configuring the BIOS boot order. This works even if only one drive is used, although gmirror(8) will not be doing any mirroring. See Ralf S. Engelschall's <rse@FreeBSD.org> excellent System Disk Mirroring HOWTO and note the implementation here is using GEOM mirror on partitions of a slice on a disk for the boot partition.

Since we're forced to use a regular 'a' boot partition there is some advntage in using a regular 'b' partion for swap. Due to the way ZFS is currently implemented there is a known issue (in FreeBSD and OpenSolaris) where ZFS needs to allocate memory to send an I/O request. When there is no memory, ZFS cannot allocate any and thus cannot swap a process out and free it. Such low memory conditions can cause the machine to effectively freeze — unable to swap out to disk right when it is most crucial to do so. See http://Lists.FreeBSD.org/pipermail/freebsd-current/2007-September/076831.html

The script assumes the FreeBSD 7 disk1 ISO to be mounted on /dist on another host and /root/.ssh/authorized_keys on that host should allow the target machine booted via the USB drive to connect without requiring a password. 

#!/bin/sh
#
# HOWTO/script to create a ZFS pool mounted as an almost bootable "root"
# partition.
#
# Adapted by Yarema  from
#	http://People.FreeBSD.org/~rse/mirror/
#	http://Wiki.FreeBSD.org/ZFSOnRoot
#	http://Wiki.FreeBSD.org/ZFS
#	http://Wiki.FreeBSD.org/ZFSTuningGuide
#
# This script will create a 512M gmirror(8) boot partition.
# A swap 'b' partition on each drive if more than one is used.
# And a 'd' partition for the zpool.
# When using more than one drive the zpool can be 'mirror'.
# When using three or more drives the zpool type can be 'raidz'.
#
# The gmirror(8) boot partition will be mounted to the /strap mountpoint
# on the zpool. /strap/boot will be nullfs mounted to the /boot mountpoint.
# /strap/rescue will be nullfs mounted to the /rescue mountpoint.
# /strap/bin and /strap/sbin will be soft-linked to /rescue.
#
# Normally even single user boot will still mount the zfs  as root.
# Putting the statically linked /rescue utilities on the boot/'a'
# partition seems like a good idea in the unlikely case that the zpool
# is unmountable.  Albeit zpool(1M) and zfs(1M) are not (yet?) built or
# installed in /rescue.
#
# WARNING: Due to the way ZFS is currently implemented there is a known
# issue (in FreeBSD and OpenSolaris) where ZFS needs to allocate memory
# to send an I/O request.  When there is no memory, ZFS cannot allocate
# any and thus cannot swap a process out and free it.  Such low memory
# conditions can cause the machine to effectively freeze -- unable to
# swap out to disk right when it is most crucial to do so.
# http://Lists.FreeBSD.org/pipermail/freebsd-current/2007-September/076831.html

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
program=`basename $0`

if [ $# -lt 1 ]; then
  echo "Usage: ${program} [mirror|raidz]  ..."
  exit 1
fi

case "$1" in
mirror|raidz|raidz[12])
  type="$1"; shift
  if [ "${type}" = 'mirror' -a $# -lt 2 ]; then
    echo "Usage:	${program} ${type}   ..."
    exit 1
  elif [ "${type}" = 'raidz2' -a $# -lt 4 ]; then
    echo "Usage:	${program} ${type}     ..."
    exit 1
  elif [ "${type}" != 'mirror' -a $# -lt 3 ]; then
    echo "Usage:	${program} ${type}    ..."
    exit 1
  fi
  ;;
esac
vdev1="$1"
vdevs="$@"

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
if [ -f "$0.rc" ];then
  . "$0.rc"
fi

# The recommended  name is simply the letter 'z' which makes output
# form mount(8), zfs(8M) and zpool(8M) easy to read for us humans.
: ${POOL:='z'}
DESTDIR="/${POOL}"

# file describing the ZFS datasets to create
: ${DATASETS:="$0.fs"}

# FreeBSD release directory to install from
: ${RELEASE:="7.0-RELEASE"}

# Server hostname to net install from
: ${SERVER:="server"}

# Kernel tunables as per http://Wiki.FreeBSD.org/ZFSTuningGuide
: ${KMEMSIZE:="512M"}

# Maximum installed Megabytes of RAM the system is likely to have.
# Used for calculating the size of the swap partision(s).
if [ -z "${MAXRAM}" ]; then
  MAXRAM=$(expr $(expr $(sysctl -n hw.physmem) / 1024 / 1024 / 1024 + 1) \* 1024)
fi

# When setting up a single drive set swapsize to double the ${MAXRAM}
# With more than one drive swap will be striped across all drives
# effectively making it ${MAXRAM} times the number of drives.
if [ "${vdev1}" = "${vdevs}" ];then
  swapsize=$(expr ${MAXRAM} \* 2)
else
  swapsize=${MAXRAM}
fi

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
ask() {
  local question default answer
  question=$1
  default=$2
  read -p "${question} [${default}]? " answer
  if [ -z "${answer}" ]; then
    answer=${default}
  fi
  echo ${answer}
}

yesno() {
  local question default answer
  question=$1
  default=$2
  while :; do
    answer=$(ask "${question}" "${default}")
    case "${answer}" in
    [Yy]*)	return 0;;
    [Nn]*)	return 1;;
    esac
    echo "Please answer yes or no."
  done
}

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
if yesno "Create one slice covering the entire disk(s)" n; then
  { # Wipe out any prior zpool, gmirror, fdisk and bsdlabel meta data.
    umount ${DESTDIR}/strap/boot
    umount ${DESTDIR}/strap/rescue
    umount ${DESTDIR}/strap
    zpool destroy ${POOL}
    rm -f /boot/zfs/zpool.cache
    eval "gmirror remove -v boot `echo ${vdevs} | sed -E 's/[[:<:]][[:alnum:]]+[[:>:]]/&s1a/g'`"
  } > /dev/null 2>&1
  for d in ${vdevs}; do
    dd if=/dev/zero of=/dev/${d} bs=32m count=17
    fdisk -BIv /dev/${d}
  done
fi

if yesno "Initialize the BSD label" y; then
  for d in ${vdevs}; do
    bsdlabel -wB /dev/${d}s1
  done
fi

# Create a bsdlabel where the 'a' bootable partition is 512M plus one
# extra sector for gmirror metadata.  The default /boot directory with a
# FreeBSD 7.0 GENERIC kernel and all the modules takes up about 178MB.
# 256MB can be a little tight if you need to keep a backup kernel or two.
# 512MB is still a good size for the boot partition.
#
# Create a large enough 'b' swap partition to be used for a swap backed
# /tmp mdmfs, /usr/obj mdmfs, and/or any other partitions you do not care
# to keep between reboots which might benefit from the extra speed of mfs.
# According to zfs(1M), using a ZFS volume as a dump device is not supported.
# Setting 'dumpdev' to the swap partition requires that it be at least as
# big as the installed RAM. When setting up a single drive, the swapsize
# will default to double the maximum installed RAM the system is likely to
# have plus what's left from rounding the 'd' partition down to the nearest
# Gigabyte. With more than one drive swap will be striped across all drives 
# and only needs to be as large on each drive as the installed RAM so that
# a coredump can fit. 
#
# Allocate the 'd' partition to be used by the "root" ZFS pool rounded down to
# the nearest Gigabyte with the remainder going to the 'b' swap partition.
bsdlabel /dev/${vdev1}s1 | awk -v s=${swapsize} '
/^ +c: / {
  a = 512 * 1024 * 2 + 1
  b = s * 1024 * 2
  c = $2
  d = c - 16 - a - b
}
END {
  print "8 partitions:"
  print "#        size   offset    fstype"
  printf("  a:  %d       16    4.2BSD\n", a)
  print  "  b:        *        *      swap"
  print  "  c:        *        0    unused"
  printf("  d:     %dG        *    unused\n", d / 2 / 1024 / 1024 )
}
' - > /tmp/bsdlabel.txt
bsdlabel -R /dev/${vdev1}s1 /tmp/bsdlabel.txt
bsdlabel /dev/${vdev1}s1
while yesno "(Re)Edit the BSD label" n; do
  bsdlabel -e /dev/${vdev1}s1
  bsdlabel /dev/${vdev1}s1
done
bsdlabel /dev/${vdev1}s1 > /tmp/bsdlabel.txt
if yesno "Apply the same BSD label to all mirrored devices" y; then
  for d in ${vdevs}; do
    bsdlabel -R /dev/${d}s1 /tmp/bsdlabel.txt
  done
fi

# Create a gmirror of the 'a' partition across all the devices
eval "gmirror label -v -h -b load boot `echo ${vdevs} | sed -E 's/[[:<:]][[:alnum:]]+[[:>:]]/&s1a/g'`"

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
if yesno "Create the ZFS pool on the 'd' partition(s)" y; then
  eval "zpool create ${POOL} ${type} `echo ${vdevs} | sed -E 's/[[:<:]][[:alnum:]]+[[:>:]]/&s1d/g'`"
  zfs set atime=off ${POOL}
  while read filesystem options; do
    case "${filesystem}" in
    /*)
      command="zfs create"
      for option in ${options};do
	command="${command} -o ${option}"
      done
      eval `echo "${command} ${POOL}${filesystem}" | sed -E 's/-[[:<:]]o[[:>:]][[:space:]]+-[[:<:]]V[[:>:]][[:space:]]+-[[:<:]]o[[:>:]]/-V/g'`
      zfs get mountpoint,compression,exec,setuid ${POOL}${filesystem}
      # Only set mountpoint for top level filesysytem
      # Let the child filesystem(s) inherit the moutpoint
      if echo "${filesystem}" | egrep '^/[^/]+$' > /dev/null 2>&1; then
	# Exclude volumes since they do not have the moutpoint property
	if echo "${command}" | egrep -v '[[:space:]]+-V[[:space:]]+' > /dev/null 2>&1; then
	  mountpoints="${mountpoints} ${filesystem}" 
	fi
      fi
      ;;
    *)
      continue
      ;;
    esac
  done < ${DATASETS}
fi

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
# Create bootstrap directory where the boot file system will be mounted
mkdir -p ${DESTDIR}/strap
newfs -U /dev/mirror/boot
mount /dev/mirror/boot ${DESTDIR}/strap
mkdir -p ${DESTDIR}/strap/boot ${DESTDIR}/strap/rescue ${DESTDIR}/boot ${DESTDIR}/rescue
# mount_nullfs here is the same as "ln -s strap/boot ${DESTDIR}/boot"
# but more resiliant to install scripts unlinking files before untarring.
mount -t nullfs ${DESTDIR}/strap/boot ${DESTDIR}/boot
mount -t nullfs ${DESTDIR}/strap/rescue ${DESTDIR}/rescue
ln -s rescue ${DESTDIR}/strap/bin
ln -s rescue ${DESTDIR}/strap/sbin

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
dists="base games manpages info dict"
for i in ${dists}; do
  echo "  Extracting the ${i} distribution into ${DESTDIR}..."
  ssh ${SERVER} "cat /dist/${RELEASE}/${i}/${i}.??"	| tar --unlink -xpzf - -C ${DESTDIR}
done

echo "  Extracting the GENERIC kernel into ${DESTDIR}/boot/"
ssh ${SERVER} "cat /dist/${RELEASE}/kernels/generic.??"	| tar --unlink -xpzf - -C ${DESTDIR}/boot && ln -f ${DESTDIR}/boot/GENERIC/* ${DESTDIR}/boot/kernel/

if yesno "Install /usr/src ?" n; then
  dists="base bin cddl contrib crypto etc games gnu include krb5 lib libexec release rescue sbin secure share sys tools ubin usbin"
  for i in ${dists}; do
    echo "  Extracting source component: ${i}"
    ssh ${SERVER} "cat /dist/${RELEASE}/src/s${i}.??"	| tar --unlink -xpzf - -C ${DESTDIR}/usr/src
  done
fi

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
if [ -f $0.local ];then
  . $0.local
fi

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
echo "dumpdev=\"${vdev1}s1b\"	# Set device for crash dumps" >> ${DESTDIR}/boot/loader.conf.local
echo -n "vfs.root.mountfrom=\"zfs:${POOL}\"" >> ${DESTDIR}/boot/loader.conf.local
echo "	# Specify root partition in a way the kernel understands" >> ${DESTDIR}/boot/loader.conf.local
echo "vm.kmem_size=\"${KMEMSIZE}\"		# Sets the size of kernel memory (bytes)" >> ${DESTDIR}/boot/loader.conf.local
echo "vm.kmem_size_max=\"${KMEMSIZE}\"		# used by in-kernel malloc(9)" >> ${DESTDIR}/boot/loader.conf.local
echo "nullfs_load=\"YES\"		# Null filesystem" >> ${DESTDIR}/boot/loader.conf.local
echo "zfs_load=\"YES\"			# ZFS" >> ${DESTDIR}/boot/loader.conf.local
echo "geom_eli_load=\"YES\"		# Disk encryption driver (see geli(8))" >> ${DESTDIR}/boot/loader.conf.local
echo "geom_mirror_load=\"YES\"		# RAID1 disk driver (see gmirror(8))" >> ${DESTDIR}/boot/loader.conf.local

echo "# Device		Mountpoint	FStype	Options			Dump	Pass#" > ${DESTDIR}/etc/fstab
for sw in `echo ${vdevs} | sed -E 's/[[:<:]][[:alnum:]]+[[:>:]]/&s1b/g'`; do
  echo "/dev/${sw}.eli		none		swap	sw			0	0" >> ${DESTDIR}/etc/fstab
done
echo "${POOL}			/		zfs	rw,noatime		0	0" >> ${DESTDIR}/etc/fstab
echo "/dev/mirror/boot	/strap		ufs	rw,noatime,nosuid	1	1" >> ${DESTDIR}/etc/fstab
echo "/strap/boot		/boot		nullfs	rw			0	0" >> ${DESTDIR}/etc/fstab
echo "/strap/rescue		/rescue		nullfs	rw			0	0" >> ${DESTDIR}/etc/fstab
echo "tmpfs			/tmp		tmpfs	rw,nosuid		0	0" >> ${DESTDIR}/etc/fstab
echo "proc			/proc		procfs	rw			0	0" >> ${DESTDIR}/etc/fstab
echo "# Device		Mountpoint	FStype	Options			Dump	Pass#" >> ${DESTDIR}/etc/fstab
echo "/dev/acd0		/cdrom		cd9660	ro,noauto,nosuid	0	0" >> ${DESTDIR}/etc/fstab
echo "/dev/fd0		/media/fd	ufs	rw,noauto,nosuid	0	0" >> ${DESTDIR}/etc/fstab
echo "/dev/fd0		/media/floppy	msdosfs	rw,noauto,nosuid	0	0" >> ${DESTDIR}/etc/fstab

# Ensure that zfs_enable="YES" is set for /etc/rc.d/zfs
mkdir -p ${DESTDIR}/etc/rc.conf.d
echo '# ZFS support' > ${DESTDIR}/etc/rc.conf.d/zfs
echo 'zfs_enable="YES"	# Set to YES to automatically mount ZFS file systems' >> ${DESTDIR}/etc/rc.conf.d/zfs

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
umount ${DESTDIR}/strap/boot
umount ${DESTDIR}/strap/rescue
umount ${DESTDIR}/strap

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
zfs set readonly=on ${POOL}/var/empty
zfs unshare -a
zfs unmount -a -f
# At the end, set mount point to 'legacy' so ZFS won't try to mount it automatically
zfs set mountpoint=legacy ${POOL}
# After install, set the real mountpoint(s)
for mp in ${mountpoints}; do
  zfs set mountpoint=${mp} ${POOL}${mp}
done
zfs list
zfs unmount -a -f
zfs volfini

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
# Ensure /boot/zfs/zpool.cache is up to date on the boot filesystem
mount /dev/mirror/boot /media
mv /boot/zfs/zpool.cache /media/boot/zfs/
umount /dev/mirror/boot

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
# EOF
ZFS filesystem definition file should be a variation of the following zfsboot.fs modified to suit your needs: 
# ZFS filesystem definition file.
#
# First column is the filesystem name starting with a slash "/".
# The rest of the line is a space/tab seperated list of options.
# To create a ZFS volume "-V " must be given after all
# the other options, if any.
#
# Lines without a slash "/" in the first colunm are ignored.
# 
# -- Yarema 
#

#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
/innodb			volblocksize=16k	-V 16g
/compat
/compat/linux
/usr
/usr/include		compression=gzip-9	exec=off	setuid=off
/usr/local
/usr/local/etc		compression=on				setuid=off
/usr/local/include	compression=gzip-9	exec=off	setuid=off
/usr/local/info		compression=gzip-9	exec=off	setuid=off
/usr/local/man		compression=gzip-9	exec=off	setuid=off
/usr/local/share	compression=gzip-9			setuid=off
/usr/local/src		compression=gzip-9	exec=off	setuid=off
/usr/local/translations	compression=gzip-9	exec=off	setuid=off
/usr/local/www		compression=gzip-9
/usr/ports		compression=gzip-9			setuid=off
/usr/ports/distfiles	compression=off		exec=off	setuid=off
/usr/ports/packages	compression=off		exec=off	setuid=off
/usr/pkgsrc		compression=gzip-9			setuid=off
/usr/pkgsrc/distfiles	compression=off		exec=off	setuid=off
/usr/pkgsrc/packages	compression=off		exec=off	setuid=off
/usr/share		compression=gzip-9			setuid=off
/usr/src		compression=gzip-9	exec=off	setuid=off
/usr/doc		compression=gzip-9	exec=off	setuid=off
/usr/obj							setuid=off
/var
/var/db						exec=off	setuid=off
/var/db/mysql		recordsize=16k		exec=off	setuid=off
/var/db/openldap-data	recordsize=16k		exec=off	setuid=off
/var/db/pkg		compression=gzip-9	exec=on		setuid=off
/var/db/sup		compression=gzip-9	exec=off	setuid=off
/var/empty					exec=off	setuid=off
/var/ftp							setuid=off
/var/backups		compression=gzip-9	exec=off	setuid=off
/var/crash		compression=gzip-9	exec=off	setuid=off
/var/heimdal					exec=off	setuid=off
/var/log					exec=off	setuid=off
/var/mail					exec=off	setuid=off
/var/mnogosearch				exec=off	setuid=off
/var/named							setuid=off
/var/run					exec=off	setuid=off
/var/service							setuid=off
/var/spool							setuid=off
/var/svn		compression=on		exec=off	setuid=off
/var/tmp		compression=on				setuid=off
/var/yp								setuid=off
/tftpboot		compression=gzip-9	exec=off	setuid=off
#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#===#
# EOF

Files

All of the zfsboot scripts and config files can be found here.

References

See the following URLs for further details: