Date: Sat, 17 May 2014 20:45:30 +0100 (BST) From: Gavin Atkinson <gavin@FreeBSD.org> To: Dru Lavigne <dru@FreeBSD.org> Cc: svn-doc-head@freebsd.org, svn-doc-all@freebsd.org, doc-committers@freebsd.org Subject: Re: svn commit: r44770 - head/en_US.ISO8859-1/books/handbook/config Message-ID: <alpine.BSF.2.00.1405172042470.71039@ury.york.ac.uk> In-Reply-To: <201405061418.s46EISgd036096@svn.freebsd.org> References: <201405061418.s46EISgd036096@svn.freebsd.org>
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On Tue, 6 May 2014, Dru Lavigne wrote: > Author: dru > Date: Tue May 6 14:18:28 2014 > New Revision: 44770 > URL: http://svnweb.freebsd.org/changeset/doc/44770 > > Log: > Editorial review of Swap Space section. > This really belongs in the Storage chapter and should have a reference for ZFS swap. We generally recommend against using swap on ZFS, as it can currently be unstable under low-memory or high-activity situations. This will likely be fixed in the future though. Generally, I'll create a separate gmirror partition or similar for swap, and use the rest of the disks for the ZFS partiton. Gavin > > Sponsored by: iXsystems > > Modified: > head/en_US.ISO8859-1/books/handbook/config/chapter.xml > > Modified: head/en_US.ISO8859-1/books/handbook/config/chapter.xml > ============================================================================== > --- head/en_US.ISO8859-1/books/handbook/config/chapter.xml Tue May 6 13:38:06 2014 (r44769) > +++ head/en_US.ISO8859-1/books/handbook/config/chapter.xml Tue May 6 14:18:28 2014 (r44770) > @@ -2703,9 +2703,9 @@ kern.maxvnodes: 100000</screen> > <sect1 xml:id="adding-swap-space"> > <title>Adding Swap Space</title> > > - <para>Sometimes a system requires more swap space. There are > - three ways to increase swap space: add a new hard drive, > - enable swap over <literal>NFS</literal>, or create a swap file > + <para>Sometimes a system requires more swap space. This section > + describes two methods to increase swap space: adding swap to an > + existing partition or new hard drive, and creating a swap file > on an existing partition.</para> > > <para>For information on how to encrypt swap space, which options > @@ -2713,16 +2713,16 @@ kern.maxvnodes: 100000</screen> > <xref linkend="swap-encrypting"/>.</para> > > <sect2 xml:id="new-drive-swap"> > - <title>Swap on a New or Existing Hard Drive</title> > + <title>Swap on a New Hard Drive or Existing Partition</title> > > <para>Adding a new hard drive for swap gives better performance > - than adding a partition on an existing drive. Setting up > + than using a partition on an existing drive. Setting up > partitions and hard drives is explained in > <xref linkend="disks-adding"/> while > <xref linkend="configtuning-initial"/> discusses partition > layouts and swap partition size considerations.</para> > > - <para>Use &man.swapon.8; to add a swap partition to the system. > + <para>Use <command>swapon</command> to add a swap partition to the system. > For example:</para> > > <screen>&prompt.root; <userinput>swapon <replaceable>/dev/ada1s1b</replaceable></userinput></screen> > @@ -2730,10 +2730,10 @@ kern.maxvnodes: 100000</screen> > <warning> > <para>It is possible to use any partition not currently > mounted, even if it already contains data. Using > - &man.swapon.8; on a partition that contains data will > + <command>swapon</command> on a partition that contains data will > overwrite and destroy that data. Make sure that the > partition to be added as swap is really the intended > - partition before running &man.swapon.8;.</para> > + partition before running <command>swapon</command>.</para> > </warning> > > <para>To automatically add this swap partition on boot, add an > @@ -2742,34 +2742,26 @@ kern.maxvnodes: 100000</screen> > <programlisting><replaceable>/dev/ada1s1b</replaceable> none swap sw 0 0</programlisting> > > <para>See &man.fstab.5; for an explanation of the entries in > - <filename>/etc/fstab</filename>.</para> > - </sect2> > - > - <sect2 xml:id="nfs-swap"> > - <title>Swapping over <literal>NFS</literal></title> > - > - <para>Swapping over <literal>NFS</literal> is only recommended > - when there is no local hard disk to swap to. > - <literal>NFS</literal> swapping will be limited by the > - available network bandwidth and puts an additional burden > - on &man.nfsd.8;.</para> > + <filename>/etc/fstab</filename>. More information about > + <command>swapon</command> can be found in > + &man.swapon.8;.</para> > </sect2> > > <sect2 xml:id="create-swapfile"> > - <title>Swapfiles</title> > + <title>Creating a Swap File</title> > > - <para>To create a swap file, specify its size. The following > + <para>To instead create a swap file, specify its size. The following > example creates a 64MB file named > <filename>/usr/swap0</filename>.</para> > > <example> > - <title>Creating a Swapfile on &os;</title> > + <title>Creating a Swap File on &os;</title> > > <orderedlist> > <listitem> > <para>The <filename>GENERIC</filename> kernel already > - includes the memory disk driver (&man.md.4;) required > - for this operation. When building a custom kernel, > + includes the required memory disk driver. > + When building a custom kernel, > make sure to include the following line in the custom > configuration file:</para> > > @@ -2780,31 +2772,33 @@ kern.maxvnodes: 100000</screen> > </listitem> > > <listitem> > - <para>First, create the swapfile > + <para>Create the swap file, > <filename>/usr/swap0</filename>:</para> > > - <screen>&prompt.root; <userinput>dd if=/dev/zero of=/usr/swap0 bs=1024k count=64</userinput></screen> > + <screen>&prompt.root; <userinput>dd if=/dev/zero of=<replaceable>/usr/swap0</replaceable> bs=1024k count=<replaceable>64</replaceable></userinput></screen> > </listitem> > > <listitem> > <para>Then, set proper permissions on > <filename>/usr/swap0</filename>:</para> > > - <screen>&prompt.root; <userinput>chmod 0600 /usr/swap0</userinput></screen> > + <screen>&prompt.root; <userinput>chmod 0600 <replaceable>/usr/swap0</replaceable></userinput></screen> > </listitem> > > <listitem> > <para>Enable the swap file in > <filename>/etc/rc.conf</filename>:</para> > > - <programlisting>swapfile="/usr/swap0" # Set to name of swapfile if aux swapfile desired.</programlisting> > + <programlisting>swapfile="<replaceable>/usr/swap0</replaceable>" # Set to name of swap file</programlisting> > </listitem> > > <listitem> > - <para>Reboot the machine or, to enable the swap file > - immediately, type:</para> > + <para>To enable the swap file > + immediately, specify a free memory device. Refer to > + <xref linkend="disks-virtual"/> for more information > + about memory devices.</para> > > - <screen>&prompt.root; <userinput>mdconfig -a -t vnode -f /usr/swap0 -u 0 && swapon /dev/md0</userinput></screen> > + <screen>&prompt.root; <userinput>mdconfig -a -t vnode -f <replaceable>/usr/swap0</replaceable> -u <replaceable>0</replaceable> && swapon /dev/md<replaceable>0</replaceable></userinput></screen> > </listitem> > </orderedlist> > </example> > >
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