Searching by shell globs, regular expressions, exact match, by description, or any other field in the repository database is also supported by <command>pkg search</command>. After installing <package>ports-mgmt/pkg</package> or <package>ports-mgmt/pkg-devel</package>, see <citerefentry><refentrytitle>pkg-search</refentrytitle><manvolnum>8</manvolnum></citerefentry> for more details.
<emphasis><varname>vfs.zfs.top_maxinflight</varname></emphasis> - Maxmimum number of outstanding I/Os per top-level <link linkend="zfs-term-vdev">vdev</link>. Limits the depth of the command queue to prevent high latency. The limit is per top-level vdev, meaning the limit applies to each <link linkend="zfs-term-vdev-mirror">mirror</link>, <link linkend="zfs-term-vdev-raidz">RAID-Z</link>, or other vdev independently. This value can be adjusted at any time with <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
Transitioning from userland <citerefentry><refentrytitle>natd</refentrytitle><manvolnum>8</manvolnum></citerefentry> to in-kernel <acronym>NAT</acronym> might seem seamless at first but there is small catch. When using the GENERIC kernel, <application>IPFW</application> will load the <filename>libalias.ko</filename> kernel module, when <literal>firewall_nat_enable</literal> is enabled in <filename>rc.conf</filename>. The <filename>libalias.ko</filename> kernel module only provides basic <acronym>NAT</acronym> functionality, whereas the userland implementation <citerefentry><refentrytitle>natd</refentrytitle><manvolnum>8</manvolnum></citerefentry> has all <acronym>NAT</acronym> functionality available in its userland library without any extra configuration. All functionality refers to the following kernel modules that can additionally be loaded when needed besides the standard <filename>libalias.ko</filename> kernel module: <filename>alias_cuseeme.ko</filename>, <filename>alias_ftp.ko</filename>, <filename>alias_bbt.ko</filename>, <filename>skinny.ko</filename>, <filename>irc.ko</filename>, <filename>alias_pptp.ko</filename> and <filename>alias_smedia.ko</filename> using the <literal>kld_list</literal> directive in <filename>rc.conf</filename>. If a custom kernel is used, the full functionality of the userland library can be compiled in, in the kernel, using the <option>options LIBALIAS</option>.
A <acronym>NAT</acronym> instance will also be configured. It is possible to have multiple <acronym>NAT</acronym> instances each with their own configuration. For this example only one <acronym>NAT</acronym> instance is needed, <acronym>NAT</acronym> instance number 1. The configuration can take a few options such as: <option>if</option> which indicates the public interface, <option>same_ports</option> which takes care that alliased ports and local port numbers are mapped the same, <option>unreg_only</option> will result in only unregistered (private) address spaces to be processed by the <acronym>NAT</acronym> instance, and <option>reset</option> which will help to keep a functioning <acronym>NAT</acronym> instance even when the public <acronym>IP</acronym> address of the <application>IPFW</application> machine changes. For all possible options that can be passed to a single <acronym>NAT</acronym> instance configuration consult <citerefentry><refentrytitle>ipfw</refentrytitle><manvolnum>8</manvolnum></citerefentry>. When configuring a stateful <acronym>NAT</acronym>ing firewall, it is neseccary to allow translated packets to be reinjected in the firewall for further processing. This can be achieved by disabling <option>one_pass</option> behavior at the start of the firewall script.
With in-kernel <acronym>NAT</acronym> it is necessary to disable TCP segmentation offloading (<acronym>TSO</acronym>) due to the architecture of <citerefentry><refentrytitle>libalias</refentrytitle><manvolnum>3</manvolnum></citerefentry>, a library implemented as a kernel module to provide the in-kernel <acronym>NAT</acronym> facility of <application>IPFW</application>. <acronym>TSO</acronym> can be disabled on a per network interface basis using <citerefentry><refentrytitle>ifconfig</refentrytitle><manvolnum>8</manvolnum></citerefentry> or on a system wide basis using <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>. To disable <acronym>TSO</acronym> system wide, the following must be set it <filename>/etc/sysctl.conf</filename>:
<application><trademark>VirtualBox</trademark></application> is an actively developed, complete virtualization package, that is available for most operating systems including <trademark class="registered">Windows</trademark>, <trademark class="registered">Mac OS</trademark>, <trademark class="registered">Linux</trademark> and FreeBSD. It is equally capable of running <trademark class="registered">Windows</trademark> or <trademark class="registered">UNIX</trademark>-like guests. It is released as open source software, but with closed-source components available in a separate extension pack. These components include support for USB 2.0 devices. More information may be found on the <link xlink:href="http://www.virtualbox.org/wiki/Downloads"><quote>Downloads</quote> page of the <application><trademark>VirtualBox</trademark></application> wiki</link>. Currently, these extensions are not available for FreeBSD.
The <filename>kmem</filename> address space can be increased on all FreeBSD architectures. On a test system with 1 GB of physical memory, success was achieved with these options added to <filename>/boot/loader.conf</filename>, and the system restarted:
This expands the kernel address space, allowing the <varname>vm.kvm_size</varname> tunable to be pushed beyond the currently imposed limit of 1 GB, or the limit of 2 GB for <acronym>PAE</acronym>. To find the most suitable value for this option, divide the desired address space in megabytes by four. In this example, it is <literal>512</literal> for 2 GB.
As a bare minimum, the total system memory should be at least one gigabyte. The amount of recommended <acronym>RAM</acronym> depends upon the size of the pool and which <acronym>ZFS</acronym> features are used. A general rule of thumb is 1 GB of RAM for every 1 TB of storage. If the deduplication feature is used, a general rule of thumb is 5 GB of RAM per TB of storage to be deduplicated. While some users successfully use <acronym>ZFS</acronym> with less <acronym>RAM</acronym>, systems under heavy load may panic due to memory exhaustion. Further tuning may be required for systems with less than the recommended RAM requirements.
Forcing 4 KB blocks is also useful on pools where disk upgrades are planned. Future disks are likely to use 4 KB sectors, and <varname>ashift</varname> values cannot be changed after a pool is created.
BSD-2-Clause-FreeBSD
bhy
规表示法则表达式、描述或文件库中的其他其他内容。在安装<package>ports-mgmt/pkg</package>或<package>ports-mgmt/pkg-devel</package>之后，可参考<citerefentry><refentrytitle>pkg-search</refentrytitle><manvolnum>8</manvolnum></citerefentry> 以取得更多详细信息。