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
29 The Read command reads the logical blocks specified by the command from
30 the medium and copies to the data data buffer provided. Will use stdout
31 by default if you don’t provide a file.
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34 --start-block=<slba>, -s <slba>
35 Start block.
36 --block-count, -c
38 The number of blocks to transfer. This is a zeroes based value to
39 align with the kernel’s use of this field. (ie. 0 means transfer 1
40 block).
41 --data-size=<size>, -z <size>
43 Size of data, in bytes.
44 --metadata-size=<size>, -y <size>
46 Size of metadata in bytes.
47 --data=<data-file>, -d <data-file>
49 Data file. If none provided, contents are sent to STDOUT.
50 --metadata=<metadata-file>, -M <metadata-file>
52 Metadata file, if necessary.
53 --prinfo=<prinfo>, -p <prinfo>
55 Protection Information field definition.
56 ┌────┬────────────────────────────┐
58 │Bit │ Description │
59 ├────┼────────────────────────────┤
60 │3 │ PRACT: Protection │
61 │ │ Information Action. When │
62 │ │ set to 1, PI is │
63 │ │ stripped/inserted on │
64 │ │ read/write when the block │
65 │ │ format’s metadata size is │
66 │ │ 8. When set to 0, metadata │
67 │ │ is passes. │
68 ├────┼────────────────────────────┤
69 │2:0 │ PRCHK: Protection │
70 │ │ Information Check: │
71 ├────┼────────────────────────────┤
72 │2 │ Set to 1 enables checking │
73 │ │ the guard tag │
74 ├────┼────────────────────────────┤
75 │1 │ Set to 1 enables checking │
76 │ │ the application tag │
77 ├────┼────────────────────────────┤
78 │0 │ Set to 1 enables checking │
79 │ │ the reference tag │
80 └────┴────────────────────────────┘
81 --ref-tag=<reftag>, -r <reftag>
83 Optional reftag when used with protection information.
84 --app-tag-mask=<appmask>, -m <appmask>
86 Optional application tag mask when used with protection
87 information.
88 --force-unit-access, -f
90 Set the force-unit access flag.
91 -T <type>, --dir-type=<type>
93 Optional directive type. The nvme-cli only enforces the value be in
94 the defined range for the directive type, though the NVMe
95 specifcation (1.3a) defines only one directive, 01h, for write
96 stream idenfiers.
97 -S <spec>, --dir-spec=<spec>
99 Optional field for directive specifics. When used with write
100 streams, this value is defined to be the write stream identifier.
101 The nvme-cli will not validate the stream requested is within the
102 controller’s capabilities.
103 -D <dsm>, --dsm=<dsm>
105 The optional data set management attributes for this command. The
106 argument for this is the lower 16 bits of the DSM field in a write
107 command; the upper 16 bits of the field come from the directive
108 specific field, if used. This may be used to set attributes for the
109 LBAs being written, like access frequency, type, latency, among
110 other things, as well as yet to be defined types. Please consult
111 the NVMe specification for detailed breakdown of how to use this
112 field.
113 -v, --show-cmd
115 Print out the command to be sent.
116 -w, --dry-run
118 Do not actually send the command. If want to use --dry-run option,
119 --show-cmd option must be set. Otherwise --dry-run option will be
120 ignored.
121 -t, --latency
123 Print out the latency the IOCTL took (in us).
124
126 No examples yet.
127
129 Part of the nvme-user suite
130NVMe 04/24/2020 NVME-READ(1)