NAME

       nvme-stas - NVMe over Fabrics STorage Appliance Services

INTRODUCTION

       This page describes the services provided by the nvme-stas package.

       nvme-stas is composed of two services, stafd(8) and stacd(8), running on a host computer (the NVMe Host).

   STorage Appliance Finder (stafd)
       The tasks performed by stafd include:

       •   Register for mDNS service type _nvme-disc._tcp with Avahi, the service discovery daemon. This allows
           stafd to automatically locate Central or Direct Discovery Controllers (CDC, DDC) with
           zero-configuration networking (zeroconf).  stafd also allows users to manually enter CDCs and DDCs in
           a configuration file (/etc/stas/stafd.conf) when users prefer not to enable mDNS-based zeroconf.

       •   Connect to discovered or configured CDCs or DDCs.

       •   Retrieve the list of NVMe subsystem IO Controllers or Discovery Controller referrals from the
           Discovery Log Page using the NVMe command "Get Log Page".

       •   Maintain a cache of the discovery log pages.

       •   Provide a D-Bus API where other applications can interact with stafd. This API can be used, for
           example, to retrieve the list of cached discovery log pages.

   STorage Appliance Connector (stacd)
       The tasks performed by stacd include:

       •   Read the list of storage subsystems (i.e., discovery log pages) from stafd over the D-Bus API.

       •   Similar to stafd, stacd can also read a list of storage subsystems to connect to from a configuration
           file: (/etc/stas/stacd.conf).

       •   Set up the I/O controller connections to each storage subsystem.

       •   Provide a D-Bus API where other applications can interact with stacd. For example, an application
           could retrieve the list of I/O controllers that stacd connected to.

   System configuration
       A host must be provided with a Host NQN and a Host ID.  nvme-stas will not run without these two
       mandatory configuration parameters. To follow in the footsteps of nvme-cli and libnvme, nvme-stas will
       use the same Host NQN and ID that nvme-cli and libnvme use by default. In other words, nvme-stas will
       read the Host NQN and ID from these two files by default:

       •   /etc/nvme/hostnqn

       •   /etc/nvme/hostid

       Using the same configuration files will ensure consistency between nvme-stas, nvme-cli, and libnvme. On
       the other hand, nvme-stas can operate with a different Host NQN and/or ID. In that case, one can specify
       them in /etc/stas/sys.conf.

                   A new optional configuration parameters introduced in TP8010, the
                   Host Symbolic Name, can also be specified in /etc/stas/sys.conf.
                   The documentation for /etc/stas/sys.conf
                   can be found /etc/stas/sys.conf.doc.
               .PP

SEE ALSO

       stacctl(1), stacd.conf(5), stacd.service(8), stacd(8), stafctl(1), stafd.conf(5), stafd.service(8),
       stafd(8),