1NVME-DISCOVER(1) NVMe Manual NVME-DISCOVER(1)
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6 nvme-discover - Send Get Log Page request to Discovery Controller.
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9 nvme discover
10 [--transport=<trtype> | -t <trtype>]
11 [--nqn=<subnqn> | -n <subnqn>]
12 [--traddr=<traddr> | -a <traddr>]
13 [--trsvcid=<trsvcid> | -s <trsvcid>]
14 [--host-traddr=<traddr> | -w <traddr>]
15 [--host-iface=<iface> | -f <iface>]
16 [--hostnqn=<hostnqn> | -q <hostnqn>]
17 [--hostid=<hostid> | -I <hostid>]
18 [--raw=<filename> | -r <filename>]
19 [--device=<device> | -d <device>]
20 [--cfg-file=<cfg> | -C <cfg> ]
21 [--keep-alive-tmo=<sec> | -k <sec>]
22 [--reconnect-delay=<#> | -c <#>]
23 [--ctrl-loss-tmo=<#> | -l <#>]
24 [--nr-io-queues=<#> | -i <#>]
25 [--nr-write-queues=<#> | -W <#>]
26 [--nr-poll-queues=<#> | -P <#>]
27 [--queue-size=<#> | -Q <#>]
28 [--keyring=<#> ]
29 [--tls_key=<#> ]
30 [--hdr-digest | -g]
31 [--data-digest | -G]
32 [--persistent | -p]
33 [--quiet | -S]
34 [--tls ]
35 [--dump-config | -O]
36 [--output-format=<fmt> | -o <fmt>]
37 [--force]
38 [--nbft]
39 [--no-nbft]
40 [--nbft-path=<STR>]
41
43 Send one or more Get Log Page requests to a NVMe-over-Fabrics Discovery
44 Controller.
45 If no parameters are given, then nvme discover will attempt to find a
47 /etc/nvme/discovery.conf file to use to supply a list of Discovery
48 commands to run. If no /etc/nvme/discovery.conf file exists, the
49 command will quit with an error.
50 Otherwise, a specific Discovery Controller should be specified using
52 the --transport, --traddr, and if necessary the --trsvcid flags. A
53 Discovery request will then be sent to the specified Discovery
54 Controller.
55
57 The NVMe-over-Fabrics specification defines the concept of a Discovery
58 Controller that an NVMe Host can query on a fabric network to discover
59 NVMe subsystems contained in NVMe Targets which it can connect to on
60 the network. The Discovery Controller will return Discovery Log Pages
61 that provide the NVMe Host with specific information (such as network
62 address and unique subsystem NQN) the NVMe Host can use to issue an
63 NVMe connect command to connect itself to a storage resource contained
64 in that NVMe subsystem on the NVMe Target.
65 Note that the base NVMe specification defines the NQN (NVMe Qualified
67 Name) format which an NVMe endpoint (device, subsystem, etc) must
68 follow to guarantee a unique name under the NVMe standard. In
69 particular, the Host NQN uniquely identifies the NVMe Host, and may be
70 used by the Discovery Controller to control what NVMe Target resources
71 are allocated to the NVMe Host for a connection.
72 A Discovery Controller has it’s own NQN defined in the
74 NVMe-over-Fabrics specification, nqn.2014-08.org.nvmexpress.discovery.
75 All Discovery Controllers must use this NQN name. This NQN is used by
76 default by nvme-cli for the discover command.
77
79 -t <trtype>, --transport=<trtype>
80 This field specifies the network fabric being used for a
81 NVMe-over-Fabrics network. Current string values include:
82 ┌──────┬────────────────────────────┐
84 │Value │ Definition │
85 ├──────┼────────────────────────────┤
86 │rdma │ The network fabric is an │
87 │ │ rdma network (RoCE, iWARP, │
88 │ │ Infiniband, basic rdma, │
89 │ │ etc) │
90 ├──────┼────────────────────────────┤
91 │fc │ WIP The network fabric is │
92 │ │ a Fibre Channel network. │
93 ├──────┼────────────────────────────┤
94 │tcp │ The network fabric is a │
95 │ │ TCP/IP network. │
96 ├──────┼────────────────────────────┤
97 │loop │ Connect to a NVMe over │
98 │ │ Fabrics target on the │
99 │ │ local host │
100 └──────┴────────────────────────────┘
101 -n <subnqn>, --nqn <subnqn>
103 This field specifies the name for the NVMe subsystem to connect to.
104 -a <traddr>, --traddr=<traddr>
106 This field specifies the network address of the Discovery
107 Controller. For transports using IP addressing (e.g. rdma) this
108 should be an IP-based address (ex. IPv4).
109 -s <trsvcid>, --trsvcid=<trsvcid>
111 This field specifies the transport service id. For transports using
112 IP addressing (e.g. rdma) this field is the port number. By
113 default, the IP port number for the RDMA transport is 4420.
114 -w <traddr>, --host-traddr=<traddr>
116 This field specifies the network address used on the host to
117 connect to the Controller. For TCP, this sets the source address on
118 the socket.
119 -f <iface>, --host-iface=<iface>
121 This field specifies the network interface used on the host to
122 connect to the Controller (e.g. IP eth1, enp2s0, enx78e7d1ea46da).
123 This forces the connection to be made on a specific interface
124 instead of letting the system decide.
125 -q <hostnqn>, --hostnqn=<hostnqn>
127 Overrides the default host NQN that identifies the NVMe Host. If
128 this option is not specified, the default is read from
129 /etc/nvme/hostnqn first. If that does not exist, the autogenerated
130 NQN value from the NVMe Host kernel module is used next.
131 -I <hostid>, --hostid=<hostid>
133 UUID(Universally Unique Identifier) to be discovered which should
134 be formatted.
135 -r <filename>, --raw=<filename>
137 This field will take the output of the nvme discover command and
138 dump it to a raw binary file. By default nvme discover will dump
139 the output to stdout.
140 -d <device>, --device=<device>
142 This field takes a device as input. It must be a persistent device
143 associated with a Discovery Controller previously created by the
144 command "connect-all" or "discover". <device> follows the format
145 nvme*, eg. nvme0, nvme1.
146 -C <cfg>, --config-file=<cfg>
148 Use the specified JSON configuration file instead of the default
149 /etc/nvme/config.json file or none to not read in an existing
150 configuration file. The JSON configuration file format is
151 documented in
152 https://github.com/linux-nvme/libnvme/doc/config-schema.json
153 -k <#>, --keep-alive-tmo=<#>
155 Overrides the default keep alive timeout (in seconds). This option
156 will be ignored for discovery, and it is only implemented for
157 completeness.
158 -c <#>, --reconnect-delay=<#>
160 Overrides the default delay (in seconds) before reconnect is
161 attempted after a connect loss.
162 -l <#>, --ctrl-loss-tmo=<#>
164 Overrides the default controller loss timeout period (in seconds).
165 -i <#>, --nr-io-queues=<#>
167 Overrides the default number of I/O queues create by the driver.
168 This option will be ignored for the discovery, and it is only
169 implemented for completeness.
170 -W <#>, --nr-write-queues=<#>
172 Adds additional queues that will be used for write I/O.
173 -P <#>, --nr-poll-queues=<#>
175 Adds additional queues that will be used for polling latency
176 sensitive I/O.
177 -Q <#>, --queue-size=<#>
179 Overrides the default number of elements in the I/O queues created
180 by the driver which can be found at drivers/nvme/host/fabrics.h.
181 This option will be ignored for the discovery, and it is only
182 implemented for completeness.
183 --keyring=<#>
185 Keyring for TLS key lookup.
186 --tls_key=<#>
188 TLS key for the connection (TCP).
189 -g, --hdr-digest
191 Generates/verifies header digest (TCP).
192 -G, --data-digest
194 Generates/verifies data digest (TCP).
195 -p, --persistent
197 Don’t remove the discovery controller after retrieving the
198 discovery log page.
199 --tls
201 Enable TLS encryption (TCP).
202 -S, --quiet
204 Suppress already connected errors.
205 -O, --dump-config
207 Print out resulting JSON configuration file to stdout.
208 -o <format>, --output-format=<format>
210 Set the reporting format to normal, json, or binary. Only one
211 output format can be used at a time.
212 --force
214 Disable the built-in persistent discover connection rules. Combined
215 with --persistent flag, always create new persistent discovery
216 connection.
217 --nbft
219 Only look at NBFT tables
220 --no-nbft
222 Do not look at NBFT tables
223 --nbft-path=<STR>
225 Use a user-defined path to the NBFT tables
226
228 • Query the Discover Controller with IP4 address 192.168.1.3 for all
229 resources allocated for NVMe Host name host1-rogue-nqn on the RDMA
230 network. Port 4420 is used by default:
231 # nvme discover --transport=rdma --traddr=192.168.1.3 \
233 --hostnqn=host1-rogue-nqn
234 • Issue a nvme discover command using the default system defined NBFT
236 tables:
237 # nvme discover --nbft
239 • Issue a nvme discover command with a user-defined path for the NBFT
241 table:
242 # nvme discover --nbft-path=/sys/firmware/acpi/tables/NBFT1
244 • Issue a nvme discover command using a /etc/nvme/discovery.conf
246 file:
247 # Machine default 'nvme discover' commands. Query the
249 # Discovery Controller's two ports (some resources may only
250 # be accessible on a single port). Note an official
251 # nqn (Host) name defined in the NVMe specification is being used
252 # in this example.
253 -t rdma -a 192.168.69.33 -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432
254 -t rdma -a 192.168.1.4 -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432
255 At the prompt type "nvme discover".
257
259 nvme-connect(1) nvme-connect-all(1)
260
262 This was written by Jay Freyensee[1]
263
265 Part of the nvme-user suite
266
268 1. Jay Freyensee
269 mailto:james.p.freyensee@intel.com
270NVMe 10/06/2023 NVME-DISCOVER(1)