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Wrap long lines, put some content on the same line as the opening tags, and

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properly intent nested tags to make textproc/igor happy.
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Benedict Reuschling 2018-08-19 11:51:30 +00:00
parent 3b24ec7126
commit 18da88da15
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=52156
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333
en_US.ISO8859-1/books/faq/book.xml
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@ -15,7 +15,9 @@
<!ENTITY rel2.releng "<symbol xmlns='http://docbook.org/ns/docbook'>stable/10/</symbol>"> <!ENTITY rel2.releng "<symbol xmlns='http://docbook.org/ns/docbook'>stable/10/</symbol>">
<!ENTITY rel2.relengdate "August 2015"> <!ENTITY rel2.relengdate "August 2015">
]> ]>
<book xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en"> <book xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
xml:lang="en">
<info> <info>
<title>Frequently Asked Questions for &os; <title>Frequently Asked Questions for &os;
&rel2.relx; and &rel.relx;</title> &rel2.relx; and &rel.relx;</title>
@ -546,7 +548,7 @@
<answer> <answer>
<para>Every significant release of &os; is available via <para>Every significant release of &os; is available via
anonymous FTP from the <link anonymous FTP from the <link
xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/"> &os; xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/">&os;
FTP site</link>:</para> FTP site</link>:</para>
<itemizedlist> <itemizedlist>
@ -878,7 +880,7 @@
<para>Where the format is <para>Where the format is
<literal>html-split</literal>, the files are <literal>html-split</literal>, the files are
bundled up using &man.tar.1;. The resulting bundled up using &man.tar.1;. The resulting
<filename>.tar</filename> file is then compressed <filename>.tar</filename> is then compressed
using the compression schemes detailed in the next using the compression schemes detailed in the next
point.</para> point.</para>
</listitem> </listitem>
@ -2411,19 +2413,19 @@ kern.timecounter.hardware: TSC -&gt; i8254</screen>
</question> </question>
<answer> <answer>
<para>If the installed &os; version lags <para>If the installed &os; version lags significantly
significantly behind <emphasis>-CURRENT</emphasis> or behind <emphasis>-CURRENT</emphasis> or
<emphasis>-STABLE</emphasis>, update the <emphasis>-STABLE</emphasis>, update the Ports Collection
Ports Collection using the instructions in <link using the instructions in <link
xlink:href="&url.books.handbook;/ports-using.html">Using xlink:href="&url.books.handbook;/ports-using.html">Using
the Ports Collection</link>. If the system is the Ports Collection</link>. If the system is
up-to-date, someone might have committed a change to the up-to-date, someone might have committed a change to the
port which works for <emphasis>-CURRENT</emphasis> but port which works for <emphasis>-CURRENT</emphasis> but
which broke the port for <emphasis>-STABLE</emphasis>. which broke the port for <emphasis>-STABLE</emphasis>.
<link xlink:href="https://bugs.FreeBSD.org/submit/">Submit</link> <link
xlink:href="https://bugs.FreeBSD.org/submit/">Submit</link>
a bug report, since the Ports Collection is supposed to a bug report, since the Ports Collection is supposed to
work work for both the <emphasis>-CURRENT</emphasis> and
for both the <emphasis>-CURRENT</emphasis> and
<emphasis>-STABLE</emphasis> branches.</para> <emphasis>-STABLE</emphasis> branches.</para>
</answer> </answer>
</qandaentry> </qandaentry>
@ -2696,9 +2698,8 @@ kern.timecounter.hardware: TSC -&gt; i8254</screen>
</listitem> </listitem>
<listitem> <listitem>
<para>The <command>make <para>The <command>make buildkernel</command> did not
buildkernel</command> command did not complete complete successfully. The <command>make
successfully. The <command>make
buildkernel</command> target relies on files buildkernel</command> target relies on files
generated by the <command>make buildworld</command> generated by the <command>make buildworld</command>
target to complete its job correctly.</para> target to complete its job correctly.</para>
@ -3356,8 +3357,8 @@ kern.sched.name: ULE</screen>
<answer> <answer>
<para>This section <link <para>This section <link
xlink:href="&url.books.handbook;/adding-swap-space.html">of the Handbook</link> xlink:href="&url.books.handbook;/adding-swap-space.html">of
describes how to do this.</para> the Handbook</link> describes how to do this.</para>
</answer> </answer>
</qandaentry> </qandaentry>
@ -3407,156 +3408,154 @@ kern.sched.name: ULE</screen>
</chapter> </chapter>
<chapter xml:id="all-about-zfs"> <chapter xml:id="all-about-zfs">
<title>ZFS</title> <title>ZFS</title>
<qandaset> <qandaset>
<qandaentry> <qandaentry>
<question xml:id="how-much-ram-for-zfs"> <question xml:id="how-much-ram-for-zfs">
<para>What is the minimum amount of RAM one should have to <para>What is the minimum amount of RAM one should have to
run ZFS?</para> run ZFS?</para>
</question> </question>
<answer> <answer>
<para>A minimum of 4GB of RAM is required for comfortable <para>A minimum of 4GB of RAM is required for comfortable
usage, but individual workloads can vary widely.</para> usage, but individual workloads can vary widely.</para>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry> <qandaentry>
<question xml:id="what-is-zil"> <question xml:id="what-is-zil">
<para>What is the ZIL and when does it get used?</para> <para>What is the ZIL and when does it get used?</para>
</question> </question>
<answer> <answer>
<para>The <acronym>ZIL</acronym> (<acronym>ZFS</acronym> <para>The <acronym>ZIL</acronym> (<acronym>ZFS</acronym>
intent log) is a write log used to implement posix write intent log) is a write log used to implement posix write
commitment semantics across crashes. Normally writes commitment semantics across crashes. Normally writes are
are bundled up into transaction groups and written to bundled up into transaction groups and written to disk
disk when filled (<quote>Transaction Group when filled (<quote>Transaction Group Commit</quote>).
Commit</quote>). However syscalls like &man.fsync.2; However syscalls like &man.fsync.2; require a commitment
require a commitment that the data is written to stable that the data is written to stable storage before
storage before returning. The ZIL is needed for writes returning. The ZIL is needed for writes that have been
that have been acknowledged as written but which are not acknowledged as written but which are not yet on disk as
yet on disk as part of a transaction. The transaction part of a transaction. The transaction groups are
groups are timestamped. In the event of a crash the timestamped. In the event of a crash the last valid
last valid timestamp is found and missing data is merged timestamp is found and missing data is merged in from the
in from the ZIL.</para> ZIL.</para>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry> <qandaentry>
<question xml:id="need-ssd-for-zil"> <question xml:id="need-ssd-for-zil">
<para>Do I need a SSD for ZIL?</para> <para>Do I need a SSD for ZIL?</para>
</question> </question>
<answer> <answer>
<para>By default, ZFS stores the ZIL in the pool with all <para>By default, ZFS stores the ZIL in the pool with all
the data. If an application has a heavy write load, the data. If an application has a heavy write load,
storing the ZIL in a separate device that has very fast storing the ZIL in a separate device that has very fast
synchronous, sequential write performance can improve synchronous, sequential write performance can improve
overall system. For other workloads, a SSD is unlikely overall system. For other workloads, a SSD is unlikely to
to make much of an improvement.</para> make much of an improvement.</para>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry> <qandaentry>
<question xml:id="what-is-l2arc"> <question xml:id="what-is-l2arc">
<para>What is the L2ARC?</para> <para>What is the L2ARC?</para>
</question> </question>
<answer> <answer>
<para>The <acronym>L2ARC</acronym> is a read cache stored <para>The <acronym>L2ARC</acronym> is a read cache stored on
on a fast device such as an <acronym>SSD</acronym>. a fast device such as an <acronym>SSD</acronym>. This
This cache is not persistent across reboots. Note that cache is not persistent across reboots. Note that RAM is
RAM is used as the first layer of cache and the L2ARC is used as the first layer of cache and the L2ARC is only
only needed if there is insufficient RAM.</para> needed if there is insufficient RAM.</para>
<para>L2ARC needs space in the ARC to index it. So, <para>L2ARC needs space in the ARC to index it. So,
perversely, a working set that fits perfectly in the perversely, a working set that fits perfectly in the ARC
ARC will not fit perfectly any more if a L2ARC is used will not fit perfectly any more if a L2ARC is used because
because part of the ARC is holding the L2ARC index, part of the ARC is holding the L2ARC index, pushing part
pushing part of the working set into the L2ARC which is of the working set into the L2ARC which is slower than
slower than RAM.</para> RAM.</para>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry> <qandaentry>
<question xml:id="should-enable-dedup"> <question xml:id="should-enable-dedup">
<para>Is enabling deduplication advisable?</para> <para>Is enabling deduplication advisable?</para>
</question> </question>
<answer> <answer>
<para>Generally speaking, no.</para> <para>Generally speaking, no.</para>
<para>Deduplication takes up a significant amount of RAM <para>Deduplication takes up a significant amount of RAM and
and may slow down read and write disk access times. may slow down read and write disk access times. Unless
Unless one is storing data that is very heavily one is storing data that is very heavily duplicated, such
duplicated, such as virtual machine images or user as virtual machine images or user backups, it is possible
backups, it is possible that deduplication will do more that deduplication will do more harm than good. Another
harm than good. Another consideration is the inability consideration is the inability to revert deduplication
to revert deduplication status. If data is written when status. If data is written when deduplication is enabled,
deduplication is enabled, disabling dedup will not cause disabling dedup will not cause those blocks which were
those blocks which were deduplicated to be replicated deduplicated to be replicated until they are next
until they are next modified.</para> modified.</para>
<para>Deduplication can also lead to some unexpected <para>Deduplication can also lead to some unexpected
situations. In particular, deleting files may become situations. In particular, deleting files may become much
much slower.</para> slower.</para>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry> <qandaentry>
<question xml:id="zpool-fully-full"> <question xml:id="zpool-fully-full">
<para>I cannot delete or create files on my ZFS pool. <para>I cannot delete or create files on my ZFS pool. How
How can I fix this?</para> can I fix this?</para>
</question> </question>
<answer> <answer>
<para>This could happen because the pool is 100% full. <para>This could happen because the pool is 100% full. ZFS
ZFS requires space on the disk to write transaction requires space on the disk to write transaction metadata.
metadata. To restore the pool to a usable state, To restore the pool to a usable state, truncate the file
truncate the file to delete:</para> to delete:</para>
<screen>&prompt.user; <userinput>truncate -s 0 unimportant-file</userinput></screen> <screen>&prompt.user; <userinput>truncate -s 0 unimportant-file</userinput></screen>
<para>File truncation works because a new transaction is <para>File truncation works because a new transaction is not
not started, new spare blocks are created started, new spare blocks are created instead.</para>
instead.</para>
<note> <note>
<para>On systems with additional ZFS dataset tuning, <para>On systems with additional ZFS dataset tuning, such
such as deduplication, the space may not be as deduplication, the space may not be immediately
immediately available</para> available</para>
</note> </note>
</answer> </answer>
</qandaentry> </qandaentry>
<qandaentry> <qandaentry>
<question xml:id="zfs-ssd-trim"> <question xml:id="zfs-ssd-trim">
<para>Does ZFS support TRIM for Solid State Drives?</para> <para>Does ZFS support TRIM for Solid State Drives?</para>
</question> </question>
<answer> <answer>
<para>ZFS TRIM support was added to &os;&nbsp;10-CURRENT <para>ZFS TRIM support was added to &os;&nbsp;10-CURRENT
with revision r<revnumber>240868</revnumber>. ZFS TRIM with revision r<revnumber>240868</revnumber>. ZFS TRIM
support was added to all &os;-STABLE branches in support was added to all &os;-STABLE branches in
r<revnumber>252162</revnumber> and r<revnumber>252162</revnumber> and
r<revnumber>251419</revnumber>, respectively.</para> r<revnumber>251419</revnumber>, respectively.</para>
<para>ZFS TRIM is enabled by default, and can be turned <para>ZFS TRIM is enabled by default, and can be turned off
off by adding this line to by adding this line to
<filename>/etc/sysctl.conf</filename>:</para> <filename>/etc/sysctl.conf</filename>:</para>
<programlisting>vfs.zfs.trim_disable=1</programlisting> <programlisting>vfs.zfs.trim_disable=1</programlisting>
<note> <note>
<para>ZFS TRIM may not work with all configurations, <para>ZFS TRIM may not work with all configurations, such
such as a ZFS filesystem on a GELI-backed as a ZFS filesystem on a GELI-backed device.</para>
device.</para> </note>
</note> </answer>
</answer> </qandaentry>
</qandaentry> </qandaset>
</qandaset>
</chapter> </chapter>
<chapter xml:id="admin"> <chapter xml:id="admin">
@ -3675,15 +3674,15 @@ kern.sched.name: ULE</screen>
<para>Restart the system using <userinput>boot <para>Restart the system using <userinput>boot
-s</userinput> at the loader prompt to enter single-user -s</userinput> at the loader prompt to enter single-user
mode. When prompted for a shell pathname, press mode. When prompted for a shell pathname, press
<keycap>Enter</keycap> and run <command>mount <keycap>Enter</keycap> and run <command>mount -urw
-urw /</command> to re-mount the root file system in /</command> to re-mount the root file system in
read/write mode. You may also need to run <command>mount read/write mode. You may also need to run <command>mount
-a -t ufs</command> to mount the file system where your -a -t ufs</command> to mount the file system where your
favorite editor is defined. If that editor is on favorite editor is defined. If that editor is on a
a network file system, either configure network file system, either configure the network manually
the network manually before mounting the network file before mounting the network file systems, or use an editor
systems, or use an editor which resides on a local file which resides on a local file system, such as
system, such as &man.ed.1;.</para> &man.ed.1;.</para>
<para>In order to use a full screen editor such as <para>In order to use a full screen editor such as
&man.vi.1; or &man.emacs.1;, run &man.vi.1; or &man.emacs.1;, run
@ -3709,7 +3708,7 @@ kern.sched.name: ULE</screen>
<para>See the <link <para>See the <link
xlink:href="&url.books.handbook;/printing.html">Handbook xlink:href="&url.books.handbook;/printing.html">Handbook
entry on printing</link> for troubleshooting entry on printing</link> for troubleshooting
tips.</para> tips.</para>
</answer> </answer>
</qandaentry> </qandaentry>
@ -4112,10 +4111,10 @@ options SYSVMSG # enable for messaging</programlisting>
<answer> <answer>
<para>The system is running at securelevel greater than 0. <para>The system is running at securelevel greater than 0.
Lower the securelevel and try again. For Lower the securelevel and try again. For more
more information, see <link linkend="securelevel">the <acronym>FAQ</acronym> information, see <link linkend="securelevel">the
entry on securelevel</link> and the &man.init.8; manual <acronym>FAQ</acronym> entry on securelevel</link> and
page.</para> the &man.init.8; manual page.</para>
</answer> </answer>
</qandaentry> </qandaentry>
@ -4416,7 +4415,7 @@ options SYSVMSG # enable for messaging</programlisting>
<filename>/etc/X11/xorg.conf</filename>, as seen in this <filename>/etc/X11/xorg.conf</filename>, as seen in this
example:</para> example:</para>
<programlisting>Section "InputDevice" <programlisting>Section "InputDevice"
Identifier "Mouse1" Identifier "Mouse1"
Driver "mouse" Driver "mouse"
Option "Protocol" "auto" Option "Protocol" "auto"
@ -5262,16 +5261,13 @@ Key F15 A A Menu Workplace Nop</programlisting>
</question> </question>
<answer> <answer>
<para> <para>Configure your kernel with these settings:
Configure your kernel with these settings:
<screen> <screen>include GENERIC
include GENERIC
ident GENERIC-IPV6ONLY ident GENERIC-IPV6ONLY
makeoptions MKMODULESENV+="WITHOUT_INET_SUPPORT=" makeoptions MKMODULESENV+="WITHOUT_INET_SUPPORT="
nooptions INET nooptions INET
nodevice gre nodevice gre</screen></para>
</screen>
</para>
</answer> </answer>
</qandaentry> </qandaentry>
</qandaset> </qandaset>
@ -6625,8 +6621,8 @@ hint.sio.7.irq="12"</programlisting>
<answer> <answer>
<para>See the <link <para>See the <link
xlink:href="&url.books.fdp-primer;/translations.html">Translation xlink:href="&url.books.fdp-primer;/translations.html">Translation
<acronym>FAQ</acronym></link> in the &os; Documentation Project <acronym>FAQ</acronym></link> in the &os; Documentation
Primer.</para> Project Primer.</para>
</answer> </answer>
</qandaentry> </qandaentry>
@ -6640,11 +6636,10 @@ hint.sio.7.irq="12"</programlisting>
<answer> <answer>
<para>The <systemitem <para>The <systemitem
class="fqdomainname">FreeBSD.org</systemitem> mail class="fqdomainname">FreeBSD.org</systemitem> mail
system implements some system implements some <application>Postfix</application>
<application>Postfix</application> checks on incoming mail checks on incoming mail and rejects mail that is either
and rejects mail that is either from misconfigured relays from misconfigured relays or otherwise appears likely to
or otherwise appears likely to be spam. Some of the be spam. Some of the specific requirements are:</para>
specific requirements are: </para>
<itemizedlist> <itemizedlist>
<listitem> <listitem>