1NVME-READ(1)                      NVMe Manual                     NVME-READ(1)
2
3
4

NAME

6       nvme-read - Send an NVMe Read command, provide results
7

SYNOPSIS

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]
29

DESCRIPTION

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.
34

OPTIONS

36       --start-block=<slba>, -s <slba>
37           Start block.
38
39       --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
44       --data-size=<size>, -z <size>
45           Size of data, in bytes.
46
47       --metadata-size=<size>, -y <size>
48           Size of metadata in bytes.
49
50       --data=<data-file>, -d <data-file>
51           Data file. If none provided, contents are sent to STDOUT.
52
53       --metadata=<metadata-file>, -M <metadata-file>
54           Metadata file, if necessary.
55
56       --prinfo=<prinfo>, -p <prinfo>
57           Protection Information field definition.
58
59           ┌────┬────────────────────────────┐
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
84       --ref-tag=<reftag>, -r <reftag>
85           Optional reftag when used with protection information.
86
87       --app-tag-mask=<appmask>, -m <appmask>
88           Optional application tag mask when used with protection
89           information.
90
91       --force-unit-access, -f
92           Set the force-unit access flag.
93
94       -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           specification (1.3a) defines only one directive, 01h, for write
98           stream identifiers.
99
100       -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
106       -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
116       -v, --show-cmd
117           Print out the command to be sent.
118
119       -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
124       -t, --latency
125           Print out the latency the IOCTL took (in us).
126
127       --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
131       --force
132           Ignore namespace is currently busy and performed the operation even
133           though.
134

EXAMPLES

136       No examples yet.
137

NVME

139       Part of the nvme-user suite
140
141
142
143NVMe                              11/04/2022                      NVME-READ(1)
Impressum