Information on mounting and unmounting filesystems.
Add a disk type to the vnconfig disklabel.
This commit is contained in:
Neil Blakey-Milner
parent
7bbaccde07
commit
2c7bde250c
Notes:
svn2git
2020-12-08 03:00:23 +00:00
svn path=/head/; revision=6865
2 changed files with 444 additions and 2 deletions
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@ -91,6 +91,227 @@
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</tgroup>
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</table>
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<sect2>
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<title>Slices and partitions</title>
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<para>Physical disks usually contain
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<firstterm>slices</firstterm>, unless they are
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<quote>dangerously dedicated</quote>. Slice numbers follow
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the device name, prefixed with an <literal>s</literal>:
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<quote>da0<emphasis>s1</emphasis></quote>.</para>
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<para>Slices, <quote>dangerously dedicated</quote> physical
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drives, and other drives contain
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<firstterm>partitions</firstterm>, which represented as
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letters from <literal>a</literal> to <literal>h</literal>.
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<literal>b</literal> is reserved for swap partitions, and
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<literal>c</literal> is an unused partition the size of the
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entire slice or drive. This is explained in <xref
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linkend="disks-adding" />.</para>
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</sect2>
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</sect1>
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<sect1 id="disks-mounting">
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<title>Mounting and unmounting filesystems</title>
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<para>The filesystem is best visualized as a tree,
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rooted, as it were, at <filename>/</filename>.
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<filename>/dev</filename>, <filename>/usr</filename>, and the
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other directories in the root directory are branches, which may
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have their own branches, such as
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<filename>/usr/local</filename>, and so on.</para>
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<para>There are various reasons to house certain of these
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directories on separate filesystems. <filename>/var</filename>
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contains log, spool, and various types of temporary files, and
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as such, may get filled up. Filling up the root filesystem
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isn't a good idea, so splitting <filename>/var</filename> from
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<filename>/</filename> is often a good idea.</para>
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<para>Another common reason to contain certain directory trees on
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other filesystems is if they are to be housed on separate
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physical disks, or are separate virtual disks, such as <link
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linkend="nfs">Network File System</link> mounts, or CDROM
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drives.</para>
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<sect2 id="disks-fstab">
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<title>The fstab file</title>
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<para>During the <link linkend="boot">boot process</link>,
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filesystems listed in <filename>/etc/fstab</filename> are
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automatically mounted (unless they are listed with
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<option>noauto</option>).</para>
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<para>The <filename>/etc/fstab</filename> file contains a list
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of lines of the following format:</para>
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<programlisting><replaceable>device</replaceable> <replaceable>/mount-point</replaceable> <replaceable>fstype</replaceable> <replaceable>options</replaceable> <replaceable>dumpfreq</replaceable> <replaceable>passno</replaceable></programlisting>
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<para><literal>device</literal> is a device name (which should
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exist), as explained in the <link linkend="disks-naming">Disk
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naming conventions</link> above.</para>
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<para><literal>mount-point</literal> is a directory (which
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should exist), on which to mount the filesystem.</para>
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<para><literal>fstype</literal> is the filesystem type to pass
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to &man.mount.8;. The default FreeBSD filesystem is
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<literal>ufs</literal>.</para>
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<para><literal>options</literal> is either <option>rw</option>
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for read-write filesystems, or <option>ro</option> for
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read-only filesystems, followed by any other options that may
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be needed. A common option is <option>noauto</option> for
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filesystems not normally mounted during the boot sequence.
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Other options in the &man.mount.8; manual page.</para>
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<para><literal>dumpfreq</literal> is the number of days the
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filesystem should be dumped, and <literal>passno</literal> is
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the pass number during which the filesystem is mounted during
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the boot sequence.</para>
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</sect2>
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<sect2 id="disks-mount">
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<title>The mount command</title>
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<para>The &man.mount.8; command is what is ultimately used to
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mount filesystems.</para>
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<para>In its most basic form, you use:</para>
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<informalexample>
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<screen>&prompt.root; <userinput>mount <replaceable>device</replaceable> <replaceable>mountpoint</replaceable></userinput></screen>
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</informalexample>
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<para>There are plenty of options, as mentioned in the
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&man.mount.8; manual page, but the most common are:</para>
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<variablelist>
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<title>mount options</title>
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<varlistentry>
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<term><option>-a</option></term>
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<listitem>
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<para>Mount all filesystems in
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<filename>/etc/fstab</filename>, as modified by
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<option>-t</option>, if given.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>-d</option></term>
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<listitem>
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<para>Do everything but actually mount the
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filesystem.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>-f</option></term>
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<listitem>
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<para>Force the mounting the filesystem.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>-r</option></term>
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<listitem>
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<para>Mount the filesystem read-only.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>-t</option>
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<replaceable>fstype</replaceable></term>
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<listitem>
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<para>Mount the given filesystem as the given filesystem
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type, or mount only filesystems of the given type, if
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given the <option>-a</option> option.</para>
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<para><quote>ufs</quote> is the default filesystem
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type.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>-u</option></term>
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<listitem>
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<para>Update mount options on the filesystem.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>-v</option></term>
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<listitem>
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<para>Be verbose.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>-w</option></term>
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<listitem>
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<para>Mount the filesystem read-write.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<para>The <option>-o</option> takes a comma-separated list of
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the options, including the following:</para>
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<variablelist>
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<varlistentry>
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<term>nodev</term>
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<listitem>
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<para>Do not interpret special devices on the
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filesystem. Useful security option.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>noexec</term>
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<listitem>
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<para>Do not allow execution of binaries on this
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filesystem. Useful security option.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>nosuid</term>
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<listitem>
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<para>Do not interpret setuid or setgid flags on the
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filesystem. Useful security option.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</sect2>
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<sect2 id="disks-umount">
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<title>The umount command</title>
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<para>The umount command takes, as a parameter, one of a
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mountpoint, a device name, or the <option>-a</option> or
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<option>-A</option> option.</para>
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<para>All forms take <option>-f</option> to force unmounting,
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and <option>-v</option> for verbosity.</para>
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<para><option>-a</option> and <option>-A</option> are used to
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unmount all mounted filesystems, possibly modified by the
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filesystem types listed after <option>-t</option>.
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<option>-A</option>, however, doesn't attempt to unmount the
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root filesystem.</para>
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</sect2>
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</sect1>
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<sect1 id="disks-adding">
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@ -267,7 +488,7 @@
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5120+0 records in
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5120+0 records out
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&prompt.root; <userinput>vnconfig -s labels -c vn<replaceable>0</replaceable> <replaceable>newimage</replaceable></userinput>
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&prompt.root; <userinput>disklabel -r -w vn<replaceable>0</replaceable></userinput>
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&prompt.root; <userinput>disklabel -r -w vn<replaceable>0</replaceable> auto</userinput>
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&prompt.root; <userinput>newfs vn<replaceable>0</replaceable>c</userinput>
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Warning: 2048 sector(s) in last cylinder unallocated
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/dev/rvn0c: 10240 sectors in 3 cylinders of 1 tracks, 4096 sectors
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@ -91,6 +91,227 @@
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</tgroup>
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</table>
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<sect2>
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<title>Slices and partitions</title>
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<para>Physical disks usually contain
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<firstterm>slices</firstterm>, unless they are
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<quote>dangerously dedicated</quote>. Slice numbers follow
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the device name, prefixed with an <literal>s</literal>:
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<quote>da0<emphasis>s1</emphasis></quote>.</para>
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<para>Slices, <quote>dangerously dedicated</quote> physical
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drives, and other drives contain
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<firstterm>partitions</firstterm>, which represented as
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letters from <literal>a</literal> to <literal>h</literal>.
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<literal>b</literal> is reserved for swap partitions, and
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<literal>c</literal> is an unused partition the size of the
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entire slice or drive. This is explained in <xref
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linkend="disks-adding" />.</para>
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</sect2>
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</sect1>
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<sect1 id="disks-mounting">
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<title>Mounting and unmounting filesystems</title>
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<para>The filesystem is best visualized as a tree,
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rooted, as it were, at <filename>/</filename>.
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<filename>/dev</filename>, <filename>/usr</filename>, and the
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other directories in the root directory are branches, which may
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have their own branches, such as
|
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<filename>/usr/local</filename>, and so on.</para>
|
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|
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<para>There are various reasons to house certain of these
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directories on separate filesystems. <filename>/var</filename>
|
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contains log, spool, and various types of temporary files, and
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as such, may get filled up. Filling up the root filesystem
|
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isn't a good idea, so splitting <filename>/var</filename> from
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<filename>/</filename> is often a good idea.</para>
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<para>Another common reason to contain certain directory trees on
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other filesystems is if they are to be housed on separate
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physical disks, or are separate virtual disks, such as <link
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linkend="nfs">Network File System</link> mounts, or CDROM
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drives.</para>
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<sect2 id="disks-fstab">
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<title>The fstab file</title>
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<para>During the <link linkend="boot">boot process</link>,
|
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filesystems listed in <filename>/etc/fstab</filename> are
|
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automatically mounted (unless they are listed with
|
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<option>noauto</option>).</para>
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|
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<para>The <filename>/etc/fstab</filename> file contains a list
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of lines of the following format:</para>
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<programlisting><replaceable>device</replaceable> <replaceable>/mount-point</replaceable> <replaceable>fstype</replaceable> <replaceable>options</replaceable> <replaceable>dumpfreq</replaceable> <replaceable>passno</replaceable></programlisting>
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<para><literal>device</literal> is a device name (which should
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exist), as explained in the <link linkend="disks-naming">Disk
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naming conventions</link> above.</para>
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<para><literal>mount-point</literal> is a directory (which
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should exist), on which to mount the filesystem.</para>
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<para><literal>fstype</literal> is the filesystem type to pass
|
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to &man.mount.8;. The default FreeBSD filesystem is
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<literal>ufs</literal>.</para>
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|
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<para><literal>options</literal> is either <option>rw</option>
|
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for read-write filesystems, or <option>ro</option> for
|
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read-only filesystems, followed by any other options that may
|
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be needed. A common option is <option>noauto</option> for
|
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filesystems not normally mounted during the boot sequence.
|
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Other options in the &man.mount.8; manual page.</para>
|
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|
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<para><literal>dumpfreq</literal> is the number of days the
|
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filesystem should be dumped, and <literal>passno</literal> is
|
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the pass number during which the filesystem is mounted during
|
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the boot sequence.</para>
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</sect2>
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<sect2 id="disks-mount">
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<title>The mount command</title>
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|
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<para>The &man.mount.8; command is what is ultimately used to
|
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mount filesystems.</para>
|
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|
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<para>In its most basic form, you use:</para>
|
||||
|
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<informalexample>
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<screen>&prompt.root; <userinput>mount <replaceable>device</replaceable> <replaceable>mountpoint</replaceable></userinput></screen>
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</informalexample>
|
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|
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<para>There are plenty of options, as mentioned in the
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&man.mount.8; manual page, but the most common are:</para>
|
||||
|
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<variablelist>
|
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<title>mount options</title>
|
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|
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<varlistentry>
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<term><option>-a</option></term>
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|
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<listitem>
|
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<para>Mount all filesystems in
|
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<filename>/etc/fstab</filename>, as modified by
|
||||
<option>-t</option>, if given.</para>
|
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</listitem>
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</varlistentry>
|
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|
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<varlistentry>
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<term><option>-d</option></term>
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|
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<listitem>
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||||
<para>Do everything but actually mount the
|
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filesystem.</para>
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</listitem>
|
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</varlistentry>
|
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|
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<varlistentry>
|
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<term><option>-f</option></term>
|
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|
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<listitem>
|
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<para>Force the mounting the filesystem.</para>
|
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</listitem>
|
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</varlistentry>
|
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|
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<varlistentry>
|
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<term><option>-r</option></term>
|
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|
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<listitem>
|
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<para>Mount the filesystem read-only.</para>
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||||
</listitem>
|
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</varlistentry>
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|
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<varlistentry>
|
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<term><option>-t</option>
|
||||
<replaceable>fstype</replaceable></term>
|
||||
|
||||
<listitem>
|
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<para>Mount the given filesystem as the given filesystem
|
||||
type, or mount only filesystems of the given type, if
|
||||
given the <option>-a</option> option.</para>
|
||||
|
||||
<para><quote>ufs</quote> is the default filesystem
|
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type.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><option>-u</option></term>
|
||||
|
||||
<listitem>
|
||||
<para>Update mount options on the filesystem.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><option>-v</option></term>
|
||||
|
||||
<listitem>
|
||||
<para>Be verbose.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
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|
||||
<varlistentry>
|
||||
<term><option>-w</option></term>
|
||||
|
||||
<listitem>
|
||||
<para>Mount the filesystem read-write.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
|
||||
<para>The <option>-o</option> takes a comma-separated list of
|
||||
the options, including the following:</para>
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term>nodev</term>
|
||||
|
||||
<listitem>
|
||||
<para>Do not interpret special devices on the
|
||||
filesystem. Useful security option.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>noexec</term>
|
||||
|
||||
<listitem>
|
||||
<para>Do not allow execution of binaries on this
|
||||
filesystem. Useful security option.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>nosuid</term>
|
||||
|
||||
<listitem>
|
||||
<para>Do not interpret setuid or setgid flags on the
|
||||
filesystem. Useful security option.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</sect2>
|
||||
|
||||
<sect2 id="disks-umount">
|
||||
<title>The umount command</title>
|
||||
|
||||
<para>The umount command takes, as a parameter, one of a
|
||||
mountpoint, a device name, or the <option>-a</option> or
|
||||
<option>-A</option> option.</para>
|
||||
|
||||
<para>All forms take <option>-f</option> to force unmounting,
|
||||
and <option>-v</option> for verbosity.</para>
|
||||
|
||||
<para><option>-a</option> and <option>-A</option> are used to
|
||||
unmount all mounted filesystems, possibly modified by the
|
||||
filesystem types listed after <option>-t</option>.
|
||||
<option>-A</option>, however, doesn't attempt to unmount the
|
||||
root filesystem.</para>
|
||||
</sect2>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="disks-adding">
|
||||
|
|
@ -267,7 +488,7 @@
|
|||
5120+0 records in
|
||||
5120+0 records out
|
||||
&prompt.root; <userinput>vnconfig -s labels -c vn<replaceable>0</replaceable> <replaceable>newimage</replaceable></userinput>
|
||||
&prompt.root; <userinput>disklabel -r -w vn<replaceable>0</replaceable></userinput>
|
||||
&prompt.root; <userinput>disklabel -r -w vn<replaceable>0</replaceable> auto</userinput>
|
||||
&prompt.root; <userinput>newfs vn<replaceable>0</replaceable>c</userinput>
|
||||
Warning: 2048 sector(s) in last cylinder unallocated
|
||||
/dev/rvn0c: 10240 sectors in 3 cylinders of 1 tracks, 4096 sectors
|
||||
|
|
|
|||
Loading…
Reference in a new issue