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NAMEnvme-discover - Send Get Log Page request to Discovery Controller. SYNOPSISnvme discover [--transport=<trtype> | -t <trtype>] DESCRIPTIONSend one or more Get Log Page requests to a NVMe-over-Fabrics Discovery Controller. If no parameters are given, then nvme discover will attempt to find a /usr/local/etc/nvme/discovery.conf file to use to supply a list of Discovery commands to run. If no /usr/local/etc/nvme/discovery.conf file exists, the command will quit with an error. Otherwise, a specific Discovery Controller should be specified using the --transport, --traddr, and if necessary the --trsvcid flags. A Discovery request will then be sent to the specified Discovery Controller. BACKGROUNDThe NVMe-over-Fabrics specification defines the concept of a Discovery Controller that an NVMe Host can query on a fabric network to discover NVMe subsystems contained in NVMe Targets which it can connect to on the network. The Discovery Controller will return Discovery Log Pages that provide the NVMe Host with specific information (such as network address and unique subsystem NQN) the NVMe Host can use to issue an NVMe connect command to connect itself to a storage resource contained in that NVMe subsystem on the NVMe Target. Note that the base NVMe specification defines the NQN (NVMe Qualified Name) format which an NVMe endpoint (device, subsystem, etc) must follow to guarantee a unique name under the NVMe standard. In particular, the Host NQN uniquely identifies the NVMe Host, and may be used by the Discovery Controller to control what NVMe Target resources are allocated to the NVMe Host for a connection. A Discovery Controller has it’s own NQN defined in the NVMe-over-Fabrics specification, nqn.2014-08.org.nvmexpress.discovery. All Discovery Controllers must use this NQN name. This NQN is used by default by nvme-cli for the discover command. OPTIONS-t <trtype>, --transport=<trtype> This field specifies the network fabric being used for a
NVMe-over-Fabrics network. Current string values include:
-n <subnqn>, --nqn <subnqn> This field specifies the name for the NVMe subsystem to
connect to.
-a <traddr>, --traddr=<traddr> This field specifies the network address of the Discovery
Controller. For transports using IP addressing (e.g. rdma) this should be an
IP-based address (ex. IPv4).
-s <trsvcid>, --trsvcid=<trsvcid> This field specifies the transport service id. For
transports using IP addressing (e.g. rdma) this field is the port number. By
default, the IP port number for the RDMA transport is 4420.
-w <traddr>, --host-traddr=<traddr> This field specifies the network address used on the host
to connect to the Controller. For TCP, this sets the source address on the
socket.
-f <iface>, --host-iface=<iface> This field specifies the network interface used on the
host to connect to the Controller (e.g. IP eth1, enp2s0, enx78e7d1ea46da).
This forces the connection to be made on a specific interface instead of
letting the system decide.
-q <hostnqn>, --hostnqn=<hostnqn> Overrides the default host NQN that identifies the NVMe
Host. If this option is not specified, the default is read from
/usr/local/etc/nvme/hostnqn first. If that does not exist, the autogenerated
NQN value from the NVMe Host kernel module is used next.
-I <hostid>, --hostid=<hostid> UUID(Universally Unique Identifier) to be discovered
which should be formatted.
-r <filename>, --raw=<filename> This field will take the output of the nvme
discover command and dump it to a raw binary file. By default nvme
discover will dump the output to stdout.
-d <device>, --device=<device> This field takes a device as input. It must be a
persistent device associated with a Discovery Controller previously created by
the command "connect-all" or "discover". <device>
follows the format nvme*, eg. nvme0, nvme1.
-J <filename>, --config=<filename> Use the specified JSON configuration file instead of the
default /usr/local/etc/nvme/config.json file or none to not read in an
existing configuration file. The JSON configuration file format is documented
in
https://github.com/linux-nvme/libnvme/blob/master/doc/config-schema.json
-k <#>, --keep-alive-tmo=<#> Overrides the default keep alive timeout (in seconds).
This option will be ignored for discovery, and it is only implemented for
completeness.
-c <#>, --reconnect-delay=<#> Overrides the default delay (in seconds) before reconnect
is attempted after a connect loss.
-l <#>, --ctrl-loss-tmo=<#> Overrides the default controller loss timeout period (in
seconds).
-i <#>, --nr-io-queues=<#> Overrides the default number of I/O queues create by the
driver. This option will be ignored for the discovery, and it is only
implemented for completeness.
-W <#>, --nr-write-queues=<#> Adds additional queues that will be used for write
I/O.
-P <#>, --nr-poll-queues=<#> Adds additional queues that will be used for polling
latency sensitive I/O.
-Q <#>, --queue-size=<#> Overrides the default number of elements in the I/O
queues created by the driver which can be found at
drivers/nvme/host/fabrics.h. This option will be ignored for the discovery,
and it is only implemented for completeness.
--keyring=<#> Keyring for TLS key lookup.
--tls_key=<#> TLS key for the connection (TCP).
-g, --hdr-digest Generates/verifies header digest (TCP).
-G, --data-digest Generates/verifies data digest (TCP).
-p, --persistent Don’t remove the discovery controller after
retrieving the discovery log page.
--tls Enable TLS encryption (TCP).
--concat Enable secure concatenation (TCP).
--quiet Suppress already connected errors.
-O, --dump-config Print out resulting JSON configuration file to
stdout.
-o <fmt>, --output-format=<fmt> Set the reporting format to normal, json or
binary. Only one output format can be used at a time.
--force Disable the built-in persistent discover connection
rules. Combined with --persistent flag, always create new persistent discovery
connection.
--nbft Only look at NBFT tables
--no-nbft Do not look at NBFT tables
--nbft-path=<STR> Use a user-defined path to the NBFT tables
--context <STR> Set the execution context to <STR>. This allows to
coordinate the management of the global resources.
-o <fmt>, --output-format=<fmt> Set the reporting format to normal, json or
binary. Only one output format can be used at a time.
-v, --verbose Increase the information detail in the output.
EXAMPLES•Query the Discover Controller with IP4 address
192.168.1.3 for all resources allocated for NVMe Host name host1-rogue-nqn on
the RDMA network. Port 4420 is used by default:
# nvme discover --transport=rdma --traddr=192.168.1.3 \ --hostnqn=host1-rogue-nqn •Issue a nvme discover command using the
default system defined NBFT tables:
# nvme discover --nbft •Issue a nvme discover command with a
user-defined path for the NBFT table:
# nvme discover --nbft-path=/sys/firmware/acpi/tables/NBFT1 •Issue a nvme discover command using a
/usr/local/etc/nvme/discovery.conf file:
# Machine default 'nvme discover' commands. Query the # Discovery Controller's two ports (some resources may only # be accessible on a single port). Note an official # nqn (Host) name defined in the NVMe specification is being used # in this example. -t rdma -a 192.168.69.33 -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432 -t rdma -a 192.168.1.4 -s 4420 -q nqn.2014-08.com.example:nvme:nvm-subsystem-sn-d78432 At the prompt type "nvme discover". SEE ALSOnvme-connect(1) nvme-connect-all(1) AUTHORSThis was written by Jay Freyensee[1] NVMEPart of the nvme-user suite NOTES
mailto:james.p.freyensee@intel.com
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