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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
SPDX-License-Identifier: Apache-2.0
Copyright (c) 2021, Dell Inc. or its subsidiaries. All rights reserved.
-->
<refentry id="nvme-stas">
<refentryinfo>
<title>nvme-stas</title>
<productname>nvme-stas</productname>
<author>
<personname>
<honorific>Mr</honorific>
<firstname>Martin</firstname>
<surname>Belanger</surname>
</personname>
<affiliation>
<orgname>Dell, Inc.</orgname>
</affiliation>
</author>
</refentryinfo>
<refmeta>
<refentrytitle>nvme-stas</refentrytitle>
<manvolnum>7</manvolnum>
</refmeta>
<refnamediv>
<refname>nvme-stas</refname>
<refpurpose>NVMe over Fabrics STorage Appliance Services</refpurpose>
</refnamediv>
<refsect1>
<title>Introduction</title>
<para>
This page describes the services provided by the <code>nvme-stas</code> package.
</para>
<para>
<code>nvme-stas</code> is composed of two services, <citerefentry><refentrytitle>stafd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
and <citerefentry><refentrytitle>stacd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
running on a host computer (the NVMe Host).
</para>
<refsect2>
<title>STorage Appliance Finder (<code>stafd</code>)</title>
<para>
The tasks performed by <code>stafd</code> include:
</para>
<itemizedlist mark='opencircle'>
<listitem>
<para>
Register for mDNS service type <parameter>_nvme-disc._tcp</parameter>
with Avahi, the service discovery daemon. This allows <code>stafd</code>
to automatically locate Central or Direct Discovery
Controllers (CDC, DDC) with zero-configuration networking
(zeroconf). <code>stafd</code> also allows users to manually enter CDCs
and DDCs in a configuration file
(<filename>/etc/stas/stafd.conf</filename>) when users
prefer not to enable mDNS-based zeroconf.
</para>
</listitem>
<listitem>
<para>
Connect to discovered or configured CDCs or DDCs.
</para>
</listitem>
<listitem>
<para>
Retrieve the list of NVMe subsystem IO Controllers or
Discovery Controller referrals from the Discovery Log Page
using the NVMe command "Get Log Page".
</para>
</listitem>
<listitem>
<para>
Maintain a cache of the discovery log pages.
</para>
</listitem>
<listitem>
<para>
Provide a D-Bus API where other applications can interact
with <code>stafd</code>. This API can be used, for example, to retrieve
the list of cached discovery log pages.
</para>
</listitem>
</itemizedlist>
</refsect2>
<refsect2>
<title>STorage Appliance Connector (<code>stacd</code>)</title>
<para>
The tasks performed by <code>stacd</code> include:
</para>
<itemizedlist mark='opencircle'>
<listitem>
<para>
Read the list of storage subsystems (i.e., discovery log pages)
from <code>stafd</code> over the D-Bus API.
</para>
</listitem>
<listitem>
<para>
Similar to <code>stafd</code>, <code>stacd</code> can also read a list of storage
subsystems to connect to from a configuration
file: (<filename>/etc/stas/stacd.conf</filename>).
</para>
</listitem>
<listitem>
<para>
Set up the I/O controller connections to each storage subsystem.
</para>
</listitem>
<listitem>
<para>
Provide a D-Bus API where other applications can interact
with <code>stacd</code>. For example, an application could retrieve the
list of I/O controllers that <code>stacd</code> connected to.
</para>
</listitem>
</itemizedlist>
</refsect2>
<refsect2>
<title>System configuration</title>
<para>
A host must be provided with a Host NQN and a Host ID. <code>nvme-stas</code>
will not run without these two mandatory configuration parameters.
To follow in the footsteps of <code>nvme-cli</code> and <code>libnvme</code>,
<code>nvme-stas</code> will use the same Host NQN and ID that
<code>nvme-cli</code> and <code>libnvme</code> use by default.
In other words, <code>nvme-stas</code> will read the Host NQN and ID
from these two files by default:
</para>
<itemizedlist mark='opencircle'>
<listitem>
<para>
<filename>/etc/nvme/hostnqn</filename>
</para>
</listitem>
<listitem>
<para>
<filename>/etc/nvme/hostid</filename>
</para>
</listitem>
</itemizedlist>
<para>
Using the same configuration files will ensure consistency between
<code>nvme-stas</code>, <code>nvme-cli</code>, and <code>libnvme</code>.
On the other hand, <code>nvme-stas</code> can operate with a
different Host NQN and/or ID. In that case, one can specify them
in <filename>/etc/stas/sys.conf</filename>.
</para>
A new optional configuration parameters introduced in TP8010, the
Host Symbolic Name, can also be specified in <filename>/etc/stas/sys.conf</filename>.
The documentation for <filename>/etc/stas/sys.conf</filename>
can be found <filename>/etc/stas/sys.conf.doc</filename>.
<para>
</para>
</refsect2>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>stacctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>stacd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>stacd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>stacd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>stafctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>stafd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>stafd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>stafd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
</para>
</refsect1>
</refentry>
|
