1NVME-DISCOVER(1)                  NVMe Manual                 NVME-DISCOVER(1)
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NAME

6       nvme-discover - Send Get Log Page request to Discovery Controller.
7

SYNOPSIS

9       nvme discover
10                       [--transport=<trtype>     | -t <trtype>]
11                       [--traddr=<traddr>        | -a <traddr>]
12                       [--trsvcid=<trsvcid>      | -s <trsvcid>]
13                       [--host-traddr=<traddr>   | -w <traddr>]
14                       [--hostnqn=<hostnqn>      | -q <hostnqn>]
15                       [--hostid=<hostid>        | -I <hostid>]
16                       [--raw=<filename>         | -r <filename>]
17                       [--keep-alive-tmo=<sec>   | -k <sec>]
18                       [--reconnect-delay=<#>    | -c <#>]
19                       [--ctrl-loss-tmo=<#>      | -l <#>]
20                       [--hdr_digest             | -g]
21                       [--data_digest            | -G]
22                       [--nr-io-queues=<#>       | -i <#>]
23                       [--nr-write-queues=<#>    | -W <#>]
24                       [--nr-poll-queues=<#>     | -P <#>]
25                       [--queue-size=<#>         | -Q <#>]
26                       [--persistent             | -p]
27                       [--quiet                  | -S]
28

DESCRIPTION

30       Send one or more Get Log Page requests to a NVMe-over-Fabrics Discovery
31       Controller.
32
33       If no parameters are given, then nvme discover will attempt to find a
34       /etc/nvme/discovery.conf file to use to supply a list of Discovery
35       commands to run. If no /etc/nvme/discovery.conf file exists, the
36       command will quit with an error.
37
38       Otherwise, a specific Discovery Controller should be specified using
39       the --transport, --traddr, and if necessary the --trsvcid flags. A
40       Diѕcovery request will then be sent to the specified Discovery
41       Controller.
42

BACKGROUND

44       The NVMe-over-Fabrics specification defines the concept of a Discovery
45       Controller that an NVMe Host can query on a fabric network to discover
46       NVMe subsystems contained in NVMe Targets which it can connect to on
47       the network. The Discovery Controller will return Discovery Log Pages
48       that provide the NVMe Host with specific information (such as network
49       address and unique subsystem NQN) the NVMe Host can use to issue an
50       NVMe connect command to connect itself to a storage resource contained
51       in that NVMe subsystem on the NVMe Target.
52
53       Note that the base NVMe specification defines the NQN (NVMe Qualified
54       Name) format which an NVMe endpoint (device, subsystem, etc) must
55       follow to guarantee a unique name under the NVMe standard. In
56       particular, the Host NQN uniquely identifies the NVMe Host, and may be
57       used by the the Discovery Controller to control what NVMe Target
58       resources are allocated to the NVMe Host for a connection.
59
60       A Discovery Controller has it’s own NQN defined in the
61       NVMe-over-Fabrics specification, nqn.2014-08.org.nvmexpress.discovery.
62       All Discovery Controllers must use this NQN name. This NQN is used by
63       default by nvme-cli for the discover command.
64

OPTIONS

66       -t <trtype>, --transport=<trtype>
67           This field specifies the network fabric being used for a
68           NVMe-over-Fabrics network. Current string values include:
69
70           ┌──────┬────────────────────────────┐
71           │Value │ Definition                 │
72           ├──────┼────────────────────────────┤
73           │rdma  │ The network fabric is an   │
74           │      │ rdma network (RoCE, iWARP, │
75           │      │ Infiniband, basic rdma,    │
76           │      │ etc)                       │
77           ├──────┼────────────────────────────┤
78           │fc    │ WIP The network fabric is  │
79           │      │ a Fibre Channel network.   │
80           ├──────┼────────────────────────────┤
81           │loop  │ Connect to a NVMe over     │
82           │      │ Fabrics target on the      │
83           │      │ local host                 │
84           └──────┴────────────────────────────┘
85
86       -a <traddr>, --traddr=<traddr>
87           This field specifies the network address of the Discovery
88           Controller. For transports using IP addressing (e.g. rdma) this
89           should be an IP-based (ex. IPv4) address.
90
91       -s <trsvcid>, --trsvcid=<trsvcid>
92           This field specifies the transport service id. For transports using
93           IP addressing (e.g. rdma) this field is the port number. By
94           default, the IP port number for the RDMA transport is 4420.
95
96       -w <traddr>, --host-traddr=<traddr>
97           This field specifies the network address used on the host to
98           connect to the Discovery Controller.
99
100       -q <hostnqn>, --hostnqn=<hostnqn>
101           Overrides the default host NQN that identifies the NVMe Host. If
102           this option is not specified, the default is read from
103           /etc/nvme/hostnqn first. If that does not exist, the autogenerated
104           NQN value from the NVMe Host kernel module is used next.
105
106       -I <hostid>, --hostid=<hostid>
107           UUID(Universally Unique Identifier) to be discovered which should
108           be formatted.
109
110       -r <filename>, --raw=<filename>
111           This field will take the output of the nvme discover command and
112           dump it to a raw binary file. By default nvme discover will dump
113           the output to stdout.
114
115       -k <#>, --keep-alive-tmo=<#>
116           Overrides the default dealy (in seconds) for keep alive. This
117           option will be ignored for the discovery, and it is only
118           implemented for completeness.
119
120       -c <#>, --reconnect-delay=<#>
121           Overrides the default delay (in seconds) before reconnect is
122           attempted after a connect loss.
123
124       -l <#>, --ctrl-loss-tmo=<#>
125           Overrides the default controller loss timeout period (in seconds).
126
127       -g, --hdr_digest
128           Generates/verifies header digest (TCP).
129
130       -G, --data_digest
131           Generates/verifies data digest (TCP).
132
133       -i <#>, --nr-io-queues=<#>
134           Overrides the default number of I/O queues create by the driver.
135           This option will be ignored for the discovery, and it is only
136           implemented for completeness.
137
138       -W <#>, --nr-write-queues=<#>
139           Adds additional queues that will be used for write I/O.
140
141       -P <#>, --nr-poll-queues=<#>
142           Adds additional queues that will be used for polling latency
143           sensitive I/O.
144
145       -Q <#>, --queue-size=<#>
146           Overrides the default number of elements in the I/O queues created
147           by the driver which can be found at drivers/nvme/host/fabrics.h.
148           This option will be ignored for the discovery, and it is only
149           implemented for completeness.
150
151       -p, --persistent
152           Persistent discovery connection.
153
154       -S, --quiet
155           Suppress already connected errors.
156

EXAMPLES

158       ·   Query the Discover Controller with IP4 address 192.168.1.3 for all
159           resources allocated for NVMe Host name host1-rogue-nqn on the RDMA
160           network. Port 4420 is used by default:
161
162               # nvme discover --transport=rdma --traddr=192.168.1.3 \
163               --hostnqn=host1-rogue-nqn
164
165       ·   Issue a nvme discover command using a /etc/nvme/discovery.conf
166           file:
167
168               # Machine default 'nvme discover' commands.  Query the
169               # Discovery Controller's two ports (some resources may only
170               # be accessible on a single port).  Note an official
171               # nqn (Host) name defined in the NVMe specification is being used
172               # in this example.
173               -t rdma -a 192.168.69.33 -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432
174               -t rdma -a 192.168.1.4   -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432
175
176               At the prompt type "nvme discover".
177

SEE ALSO

179       nvme-connect(1) nvme-connect-all(1)
180

AUTHORS

182       This was written by Jay Freyensee[1]
183

NVME

185       Part of the nvme-user suite
186

NOTES

188        1. Jay Freyensee
189           mailto:james.p.freyensee@intel.com
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193NVMe                              04/24/2020                  NVME-DISCOVER(1)
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