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 [--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
28 Send one or more Get Log Page requests to a NVMe-over-Fabrics Discovery
29 Controller.
30 If no parameters are given, then nvme discover will attempt to find a
32 /etc/nvme/discovery.conf file to use to supply a list of Discovery
33 commands to run. If no /etc/nvme/discovery.conf file exists, the
34 command will quit with an error.
35 Otherwise, a specific Discovery Controller should be specified using
37 the --transport, --traddr, and if necessary the --trsvcid flags. A
38 Diѕcovery request will then be sent to the specified Discovery
39 Controller.
40
42 The NVMe-over-Fabrics specification defines the concept of a Discovery
43 Controller that an NVMe Host can query on a fabric network to discover
44 NVMe subsystems contained in NVMe Targets which it can connect to on
45 the network. The Discovery Controller will return Discovery Log Pages
46 that provide the NVMe Host with specific information (such as network
47 address and unique subsystem NQN) the NVMe Host can use to issue an
48 NVMe connect command to connect itself to a storage resource contained
49 in that NVMe subsystem on the NVMe Target.
50 Note that the base NVMe specification defines the NQN (NVMe Qualified
52 Name) format which an NVMe endpoint (device, subsystem, etc) must
53 follow to guarantee a unique name under the NVMe standard. In
54 particular, the Host NQN uniquely identifies the NVMe Host, and may be
55 used by the the Discovery Controller to control what NVMe Target
56 resources are allocated to the NVMe Host for a connection.
57 A Discovery Controller has it’s own NQN defined in the
59 NVMe-over-Fabrics specification, nqn.2014-08.org.nvmexpress.discovery.
60 All Discovery Controllers must use this NQN name. This NQN is used by
61 default by nvme-cli for the discover command.
62
64 -t <trtype>, --transport=<trtype>
65 This field specifies the network fabric being used for a
66 NVMe-over-Fabrics network. Current string values include:
67 ┌──────┬────────────────────────────┐
69 │Value │ Definition │
70 ├──────┼────────────────────────────┤
71 │rdma │ The network fabric is an │
72 │ │ rdma network (RoCE, iWARP, │
73 │ │ Infiniband, basic rdma, │
74 │ │ etc) │
75 ├──────┼────────────────────────────┤
76 │fc │ WIP The network fabric is │
77 │ │ a Fibre Channel network. │
78 ├──────┼────────────────────────────┤
79 │loop │ Connect to a NVMe over │
80 │ │ Fabrics target on the │
81 │ │ local host │
82 └──────┴────────────────────────────┘
83 -a <traddr>, --traddr=<traddr>
85 This field specifies the network address of the Discovery
86 Controller. For transports using IP addressing (e.g. rdma) this
87 should be an IP-based (ex. IPv4) address.
88 -s <trsvcid>, --trsvcid=<trsvcid>
90 This field specifies the transport service id. For transports using
91 IP addressing (e.g. rdma) this field is the port number. By
92 default, the IP port number for the RDMA transport is 4420.
93 -w <traddr>, --host-traddr=<traddr>
95 This field specifies the network address used on the host to
96 connect to the Discovery Controller.
97 -q <hostnqn>, --hostnqn=<hostnqn>
99 Overrides the default host NQN that identifies the NVMe Host. If
100 this option is not specified, the default is read from
101 /etc/nvme/hostnqn first. If that does not exist, the autogenerated
102 NQN value from the NVMe Host kernel module is used next.
103 -I <hostid>, --hostid=<hostid>
105 UUID(Universally Unique Identifier) to be discovered which should
106 be formatted.
107 -r <filename>, --raw=<filename>
109 This field will take the output of the nvme discover command and
110 dump it to a raw binary file. By default nvme discover will dump
111 the output to stdout.
112 -k <#>, --keep-alive-tmo=<#>
114 Overrides the default dealy (in seconds) for keep alive.
115 -c <#>, --reconnect-delay=<#>
117 Overrides the default delay (in seconds) before reconnect is
118 attempted after a connect loss.
119 -l <#>, --ctrl-loss-tmo=<#>
121 Overrides the default controller loss timeout period (in seconds).
122 -g, --hdr_digest
124 Generates/verifies header digest (TCP).
125 -G, --data_digest
127 Generates/verifies data digest (TCP).
128 -i <#>, --nr-io-queues=<#>
130 Overrides the default number of I/O queues create by the driver.
131 -W <#>, --nr-write-queues=<#>
133 Adds additional queues that will be used for write I/O.
134 -P <#>, --nr-poll-queues=<#>
136 Adds additional queues that will be used for polling latency
137 sensitive I/O.
138 -Q <#>, --queue-size=<#>
140 Overrides the default number of elements in the I/O queues created
141 by the driver which can be found at drivers/nvme/host/fabrics.h.
142
144 · Query the Discover Controller with IP4 address 192.168.1.3 for all
145 resources allocated for NVMe Host name host1-rogue-nqn on the RDMA
146 network. Port 4420 is used by default:
147 # nvme discover --transport=rdma --traddr=192.168.1.3 \
149 --hostnqn=host1-rogue-nqn
150 · Issue a nvme discover command using a /etc/nvme/discovery.conf
152 file:
153 # Machine default 'nvme discover' commands. Query the
155 # Discovery Controller's two ports (some resources may only
156 # be accessible on a single port). Note an official
157 # nqn (Host) name defined in the NVMe specification is being used
158 # in this example.
159 -t rdma -a 192.168.69.33 -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432
160 -t rdma -a 192.168.1.4 -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432
161 At the prompt type "nvme discover".
163
165 nvme-connect(1) nvme-connect-all(1)
166
168 This was written by Jay Freyensee[1] for Keith Busch[2].
169
171 Part of the nvme-user suite
172
174 1. Jay Freyensee
175 mailto:james.p.freyensee@intel.com
176 2. Keith Busch
178 mailto:keith.busch@intel.com
179NVMe 04/08/2019 NVME-DISCOVER(1)