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

DESCRIPTION

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.
32

OPTIONS

34       --start-block=<slba>, -s <slba>
35           Start block.
36
37       --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
42       --data-size=<size>, -z <size>
43           Size of data, in bytes.
44
45       --metadata-size=<size>, -y <size>
46           Size of metadata in bytes.
47
48       --data=<data-file>, -d <data-file>
49           Data file. If none provided, contents are sent to STDOUT.
50
51       --metadata=<metadata-file>, -M <metadata-file>
52           Metadata file, if necessary.
53
54       --prinfo=<prinfo>, -p <prinfo>
55           Protection Information field defintion.
56
57           ┌────┬────────────────────────────┐
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
82       --ref-tag=<reftag>, -r <reftag>
83           Optional reftag when used with protection information.
84
85       --app-tag-mask=<appmask>, -m <appmask>
86           Optional application tag mask when used with protection
87           information.
88
89       --force-unit-access, -f
90           Set the force-unit access flag.
91
92       -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
98       -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
104       -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
114       -v, --show-cmd
115           Print out the command to be sent.
116
117       -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 optionn will be
120           ignored.
121
122       -t, --latency
123           Print out the latency the IOCTL took (in us).
124

EXAMPLES

126       No examples yet.
127

NVME

129       Part of the nvme-user suite
130
131
132
133NVMe                              06/05/2018                      NVME-READ(1)
Impressum