1NVME-READ(1) NVMe Manual NVME-READ(1)
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6 nvme-read - Send an NVMe Read command, provide results
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9 nvme-read <device> [--start-block=<slba> | -s <slba>]
10 [--block-count=<nlb> | -c <nlb>]
11 [--data-size=<size> | -z <size>]
12 [--metadata-size=<size> | -y <size>]
13 [--ref-tag=<reftag> | -r <reftag>]
14 [--data=<data-file> | -d <data-file>]
15 [--metadata=<metadata-file> | -M <metadata-file>]
16 [--prinfo=<prinfo> | -p <prinfo>]
17 [--app-tag-mask=<appmask> | -m <appmask>]
18 [--app-tag=<apptag> | -a <apptag>]
19 [--limited-retry | -l]
20 [--force-unit-access | -f]
21 [--dir-type=<type> | -T <type>]
22 [--dir-spec=<spec> | -S <spec>]
23 [--dsm=<dsm> | -D <dsm>]
24 [--show-command | -v]
25 [--dry-run | -w]
26 [--latency | -t]
27 [--storage-tag-check<storage-tag-check> | -C <storage-tag-check>]
28 [--force]
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31 The Read command reads the logical blocks specified by the command from
32 the medium and copies to the data data buffer provided. Will use stdout
33 by default if you don’t provide a file.
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36 --start-block=<slba>, -s <slba>
37 Start block.
38 --block-count, -c
40 The number of blocks to transfer. This is a zeroes based value to
41 align with the kernel’s use of this field. (ie. 0 means transfer 1
42 block).
43 --data-size=<size>, -z <size>
45 Size of data, in bytes.
46 --metadata-size=<size>, -y <size>
48 Size of metadata in bytes.
49 --data=<data-file>, -d <data-file>
51 Data file. If none provided, contents are sent to STDOUT.
52 --metadata=<metadata-file>, -M <metadata-file>
54 Metadata file, if necessary.
55 --prinfo=<prinfo>, -p <prinfo>
57 Protection Information field definition.
58 ┌────┬────────────────────────────┐
60 │Bit │ Description │
61 ├────┼────────────────────────────┤
62 │3 │ PRACT: Protection │
63 │ │ Information Action. When │
64 │ │ set to 1, PI is │
65 │ │ stripped/inserted on │
66 │ │ read/write when the block │
67 │ │ format’s metadata size is │
68 │ │ 8. When set to 0, metadata │
69 │ │ is passes. │
70 ├────┼────────────────────────────┤
71 │2:0 │ PRCHK: Protection │
72 │ │ Information Check: │
73 ├────┼────────────────────────────┤
74 │2 │ Set to 1 enables checking │
75 │ │ the guard tag │
76 ├────┼────────────────────────────┤
77 │1 │ Set to 1 enables checking │
78 │ │ the application tag │
79 ├────┼────────────────────────────┤
80 │0 │ Set to 1 enables checking │
81 │ │ the reference tag │
82 └────┴────────────────────────────┘
83 --ref-tag=<reftag>, -r <reftag>
85 Optional reftag when used with protection information.
86 --app-tag-mask=<appmask>, -m <appmask>
88 Optional application tag mask when used with protection
89 information.
90 --force-unit-access, -f
92 Set the force-unit access flag.
93 -T <type>, --dir-type=<type>
95 Optional directive type. The nvme-cli only enforces the value be in
96 the defined range for the directive type, though the NVMe
97 specifcation (1.3a) defines only one directive, 01h, for write
98 stream idenfiers.
99 -S <spec>, --dir-spec=<spec>
101 Optional field for directive specifics. When used with write
102 streams, this value is defined to be the write stream identifier.
103 The nvme-cli will not validate the stream requested is within the
104 controller’s capabilities.
105 -D <dsm>, --dsm=<dsm>
107 The optional data set management attributes for this command. The
108 argument for this is the least significant 8 bits of the DSM field
109 in a write command; the most significant 16 bits of the field come
110 from the directive specific field, if used. This may be used to set
111 attributes for the LBAs being written, like access frequency, type,
112 latency, among other things, as well as yet to be defined types.
113 Please consult the NVMe specification for detailed breakdown of how
114 to use this field.
115 -v, --show-cmd
117 Print out the command to be sent.
118 -w, --dry-run
120 Do not actually send the command. If want to use --dry-run option,
121 --show-cmd option must be set. Otherwise --dry-run option will be
122 ignored.
123 -t, --latency
125 Print out the latency the IOCTL took (in us).
126 --storage-tag-check=<storage-tag-check>, -C <storage-tag-check>
128 This bit specifies the Storage Tag field shall be checked as part
129 of end-to-end data protection processing.
130 --force
132 Ignore namespace is currently busy and perfome the operation even
133 though.
134
136 No examples yet.
137
139 Part of the nvme-user suite
140NVMe 04/11/2022 NVME-READ(1)