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en_US.ISO8859-1/books/handbook/disks/chapter.xml
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</listitem>
<listitem>
<para>Hardware or software <acronym>RAID</acronym>, which minimizes or avoids
downtime when a disk fails.</para>
<para>Hardware or software <acronym>RAID</acronym>, which
minimizes or avoids downtime when a disk fails.</para>
</listitem>
</itemizedlist>
<para>Typically, a mix of backup techniques is used. For
example, one could create a schedule to automate a weekly, full
<para>Typically, a mix of backup techniques is used. For
example, one could create a schedule to automate a weekly, full
system backup that is stored off-site and to supplement this
backup with hourly ZFS snapshots. In addition, one could make a
manual backup of individual directories or files before making
manual backup of individual directories or files before making
file edits or deletions.</para>
<para>This section describes some of the utilities which can be
used to create and manage backups on a &os; system.</para>
@ -1651,47 +1651,47 @@ cd0: Attempt to query device size failed: NOT READY, Medium not present - tray c
</indexterm>
<para>The traditional &unix; programs for backing up a file
system are &man.dump.8;, which creates the backup, and
system are &man.dump.8;, which creates the backup, and
&man.restore.8;, which restores the backup. These utilities
work at the disk block level, below the
abstractions of the files, links, and directories that are created
by file systems. Unlike other backup software,
<command>dump</command> backs up an entire file system and
is unable to backup only part of a file system or
a directory tree that spans multiple file systems.
Instead of writing files and directories, <command>dump</command>
writes the raw data blocks that comprise files and
directories.</para>
work at the disk block level, below the abstractions of the
files, links, and directories that are created by file
systems. Unlike other backup software,
<command>dump</command> backs up an entire file system and is
unable to backup only part of a file system or a directory
tree that spans multiple file systems. Instead of writing
files and directories, <command>dump</command> writes the raw
data blocks that comprise files and directories.</para>
<note>
<note>
<para>If <command>dump</command> is used on the root
directory, it will not back up <filename>/home</filename>,
<filename>/usr</filename> or many other
directories since these are typically mount points for other
file systems or symbolic links into those file
systems.</para>
<filename>/usr</filename> or many other directories since
these are typically mount points for other file systems or
symbolic links into those file systems.</para>
</note>
<para>When used to restore data,
<command>restore</command> stores temporary files in
<filename>/tmp/</filename> by default. When using a recovery
disk with a small <filename>/tmp</filename>, set
<envar>TMPDIR</envar> to a directory with more free space in
order for the restore to succeed.</para>
<para>When using <command>dump</command>, be aware that some quirks remain from its
early days in Version 6 of AT&amp;T &unix;,circa 1975. The
default parameters assume a backup to a 9-track tape, rather than
to another type of media or to the high-density tapes available today.
These defaults must be overridden on the command line.</para>
<para>When used to restore data, <command>restore</command>
stores temporary files in <filename>/tmp/</filename> by
default. When using a recovery disk with a small
<filename>/tmp</filename>, set <envar>TMPDIR</envar> to a
directory with more free space in order for the restore to
succeed.</para>
<para>When using <command>dump</command>, be aware that some
quirks remain from its early days in Version 6 of
AT&amp;T &unix;,circa 1975. The default parameters assume a
backup to a 9-track tape, rather than to another type of media
or to the high-density tapes available today. These defaults
must be overridden on the command line.</para>
<indexterm>
<primary><filename>.rhosts</filename></primary>
</indexterm>
<para>It is possible to backup a file system across the network to a
another system or to a tape drive attached to another computer.
While the &man.rdump.8; and &man.rrestore.8; utilities can be
used for this purpose, they are not considered to be secure.</para>
<para>It is possible to backup a file system across the network
to a another system or to a tape drive attached to another
computer. While the &man.rdump.8; and &man.rrestore.8;
utilities can be used for this purpose, they are not
considered to be secure.</para>
<para>Instead, one can use <command>dump</command> and
<command>restore</command> in a more secure fashion over an
@ -1708,7 +1708,7 @@ cd0: Attempt to query device size failed: NOT READY, Medium not present - tray c
targetuser@targetmachine.example.com dd of=/mybigfiles/dump-usr-l0.gz</userinput></screen>
</example>
<para>This example sets <envar>RSH</envar> in order to write the
<para>This example sets <envar>RSH</envar> in order to write the
the backup to a tape drive on a remote system over a
<acronym>SSH</acronym> connection:</para>
@ -1730,26 +1730,27 @@ cd0: Attempt to query device size failed: NOT READY, Medium not present - tray c
</indexterm>
<para>Several built-in utilities are available for backing up
and restoring specified files and directories as needed.</para>
and restoring specified files and directories as
needed.</para>
<para>A good choice for making a backup of all of the files in a
directory is &man.tar.1;. This utility dates back to Version 6 of AT&amp;T
&unix; and by default assumes a recursive backup to a local tape
device. Switches can be used to instead specify the name of
a backup file.</para>
directory is &man.tar.1;. This utility dates back to Version
6 of AT&amp;T &unix; and by default assumes a recursive backup
to a local tape device. Switches can be used to instead
specify the name of a backup file.</para>
<indexterm><primary><command>tar</command></primary></indexterm>
<para>This example creates a compressed backup of the current
directory and saves it to
directory and saves it to
<filename>/tmp/mybackup.tgz</filename>. When creating a
backup file, make sure that the backup is not saved to the
same directory that is being backed up.</para>
<example>
<title>Backing Up the Current Directory With
<title>Backing Up the Current Directory With
<command>tar</command></title>
<screen>&prompt.root; <userinput>tar czvf /tmp/mybackup.tgz . </userinput></screen>
</example>
@ -1761,11 +1762,11 @@ cd0: Attempt to query device size failed: NOT READY, Medium not present - tray c
backup to restore.</para>
<example>
<title>Restoring Up the Current Directory With
<title>Restoring Up the Current Directory With
<command>tar</command></title>
<screen>&prompt.root; <userinput>tar xzvf /tmp/mybackup.tgz</userinput></screen>
</example>
</example>
<para>There are dozens of available switches which are described
in &man.tar.1;. This utility also supports the use of exclude
@ -1778,26 +1779,25 @@ cd0: Attempt to query device size failed: NOT READY, Medium not present - tray c
<secondary><command>cpio</command></secondary>
</indexterm>
<para>To create a backup using a specified list of files and
<para>To create a backup using a specified list of files and
directories, &man.cpio.1; is a good choice. Unlike
<command>tar</command>,
<command>cpio</command> does not know
how to walk the directory tree and it must be provided the list of files
to backup.</para>
<command>tar</command>, <command>cpio</command> does not know
how to walk the directory tree and it must be provided the
list of files to backup.</para>
<para>For example, a list of files can be created using
<command>ls</command> or <command>find</command>. This example
creates a recursive listing of the current directory which is
then piped to <command>cpio</command> in order to create an
output backup file named
<command>ls</command> or <command>find</command>. This
example creates a recursive listing of the current directory
which is then piped to <command>cpio</command> in order to
create an output backup file named
<filename>/tmp/mybackup.cpio</filename>.</para>
<example>
<title>Using<command>ls</command> and <command>cpio</command>
to Make a Recursive Backup of the Current Directory</title>
<screen>&prompt.root; <userinput>ls -R | cpio -ovF /tmp/mybackup.cpio</userinput></screen>
</example>
</example>
<indexterm>
<primary>backup software</primary>
@ -1807,24 +1807,24 @@ cd0: Attempt to query device size failed: NOT READY, Medium not present - tray c
<indexterm><primary>POSIX</primary></indexterm>
<indexterm><primary>IEEE</primary></indexterm>
<para>A backup utility which tries to bridge the features provided by
<command>tar</command> and <command>cpio</command> is &man.pax.1;. Over the
years, the various versions of <command>tar</command> and
<command>cpio</command> became slightly incompatible. &posix;
created <command>pax</command> which
attempts to read and write many of the various
<para>A backup utility which tries to bridge the features
provided by <command>tar</command> and <command>cpio</command>
is &man.pax.1;. Over the years, the various versions of
<command>tar</command> and <command>cpio</command> became
slightly incompatible. &posix; created <command>pax</command>
which attempts to read and write many of the various
<command>cpio</command> and <command>tar</command> formats,
plus new formats of its own.</para>
<para>The <command>pax</command> equivalent to the previous
examples would be:</para>
examples would be:</para>
<example>
<title>Backing Up the Current Directory With
<title>Backing Up the Current Directory With
<command>pax</command></title>
<screen>&prompt.root; <userinput>pax -wf /tmp/mybackup.pax .</userinput></screen>
</example>
</example>
</sect2>
<sect2 xml:id="backups-programs-amanda">
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backups. Many of these applications are client/server based
and can be used to automate the backups of a single system or
all of the computers in a network.</para>
<para>Popular utilities include
<application>Amanda</application>,
<application>Amanda</application>,
<application>Bacula</application>,
<application>rsync</application>, and
<application>duplicity</application>.
</para>
<application>duplicity</application>.</para>
</sect2>
<sect2>
<title>Emergency Recovery</title>
<para>In addition to regular backups, it is recommended to
perform the following steps as part of an emergency
preparedness plan.</para>
<indexterm>
<primary><command>bsdlabel</command></primary>
</indexterm>
<para>In addition to regular backups, it is recommended to
perform the following steps as part of an emergency
preparedness plan.</para>
<para>Create a print copy of the output of the following
commands:</para>
<itemizedlist>
<listitem>
<para><command>gpart show</command></para>
</listitem>
<listitem>
<para><command>more /etc/fstab</command></para>
</listitem>
<listitem>
<para><command>dmesg</command></para>
</listitem>
</itemizedlist>
<indexterm>
<primary><command>bsdlabel</command></primary></indexterm>
<indexterm><primary>livefs CD</primary></indexterm>
<para>Store this printout and a copy of the installation media
in a secure location. Should an emergency restore be
needed, boot into the installation media and select
<literal>Live CD</literal> to access a rescue shell. This
rescue mode can be used to view the current state of the
system, and if needed, to reformat disks and restore data
from backups.</para>
<para>Create a print copy of the output of the following
commands:</para>
<note>
<para>The installation media
for &os;/&arch.i386;&nbsp;&rel2.current;-RELEASE does not
include a rescue shell. For this version, instead
download and burn a Livefs CD image from <uri
xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/&arch.i386;/ISO-IMAGES/&rel2.current;/&os;-&rel2.current;-RELEASE-&arch.i386;-livefs.iso">ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/&arch.i386;/ISO-IMAGES/&rel2.current;/&os;-&rel2.current;-RELEASE-&arch.i386;-livefs.iso</uri>.</para>
</note>
<itemizedlist>
<listitem>
<para><command>gpart show</command></para>
</listitem>
<para>Next, test the rescue shell and the
backups. Make notes of the procedure. Store these notes
with the media, the printouts, and the backups. These notes
may prevent the inadvertent destruction of the backups while
under the stress of performing an emergency
recovery.</para>
<listitem>
<para><command>more /etc/fstab</command></para>
</listitem>
<para>For an added measure of security, store the latest backup at a
remote location which is
physically separated from the
computers and disk drives by a significant distance.</para>
<listitem>
<para><command>dmesg</command></para>
</listitem>
</itemizedlist>
<indexterm><primary>livefs CD</primary></indexterm>
<para>Store this printout and a copy of the installation media
in a secure location. Should an emergency restore be
needed, boot into the installation media and select
<literal>Live CD</literal> to access a rescue shell. This
rescue mode can be used to view the current state of the
system, and if needed, to reformat disks and restore data
from backups.</para>
<note>
<para>The installation media for
&os;/&arch.i386;&nbsp;&rel2.current;-RELEASE does not
include a rescue shell. For this version, instead
download and burn a Livefs CD image from <uri
xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/&arch.i386;/ISO-IMAGES/&rel2.current;/&os;-&rel2.current;-RELEASE-&arch.i386;-livefs.iso">ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/&arch.i386;/ISO-IMAGES/&rel2.current;/&os;-&rel2.current;-RELEASE-&arch.i386;-livefs.iso</uri>.</para>
</note>
<para>Next, test the rescue shell and the backups. Make notes
of the procedure. Store these notes with the media, the
printouts, and the backups. These notes may prevent the
inadvertent destruction of the backups while under the stress
of performing an emergency recovery.</para>
<para>For an added measure of security, store the latest backup
at a remote location which is physically separated from the
computers and disk drives by a significant distance.</para>
</sect2>
</sect1>