1NVME-COMPARE(1)                   NVMe Manual                  NVME-COMPARE(1)
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NAME

6       nvme-compare - Send an NVMe Compare command, provide results
7

SYNOPSIS

9       nvme-compare <device> [--start-block=<slba> | -s <slba>]
10                               [--block-count=<nlb> | -c <nlb>]
11                               [--data-size=<size> | -z <size>]
12                               [--metadata-size=<metasize> | -y <metasize>]
13                               [--ref-tag=<reftag> | -r <reftag>]
14                               [--data=<data-file> | -d <data-file>]
15                               [--metadata=<meta> | -M <meta>]
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 Compare command reads the logical blocks specified by the command
30       from the medium and compares the data read to a comparison data buffer
31       transferred as part of the command. If the data read from the
32       controller and the comparison data buffer are equivalent with no
33       miscompares, then the command completes successfully. If there is any
34       miscompare, the command completes with an error of Compare Failure. If
35       metadata is provided, then a comparison is also performed for the
36       metadata.
37

OPTIONS

39       -s <slba>, --start-block=<slba>
40           64-bit address of the first block to access.
41
42       -c <nlb>, --block-count=<nlb>
43           Number of blocks to be accessed (zero-based).
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45       -z <size>, --data-size=<size>
46           Size of data to be compared in bytes.
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48       -y <metasize>, --metadata-size=<metasize>
49           Size of metadata to be trasnferred in bytes.
50
51       -r <reftag>, --ref-tag=<regtag>
52           Reference Tag for Protection Information
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54       -d <data-file>, --data=<data-file>
55           Data file.
56
57       -M <meta>, --metadata=<meta>
58           Metadata file.
59
60       -p <prinfo>, --prinfo=<prinfo>
61           Protection Information and check field.
62
63       +
64
65       ┌────┬────────────────────────────┐
66       │    │                            │
67       │Bit │ Description                │
68       ├────┼────────────────────────────┤
69       │    │                            │
70       │3   │ PRACT: Protection          │
71       │    │ Information Action. When   │
72       │    │ set to 1, PI is            │
73       │    │ stripped/inserted on       │
74       │    │ read/write when the block  │
75       │    │ format’s metadata size is  │
76       │    │ 8. When set to 0, metadata │
77       │    │ is passes.                 │
78       ├────┼────────────────────────────┤
79       │    │                            │
80       │2:0 │ PRCHK: Protection          │
81       │    │ Information Check:         │
82       ├────┼────────────────────────────┤
83       │    │                            │
84       │2   │ Set to 1 enables checking  │
85       │    │ the guard tag              │
86       ├────┼────────────────────────────┤
87       │    │                            │
88       │1   │ Set to 1 enables checking  │
89       │    │ the application tag        │
90       ├────┼────────────────────────────┤
91       │    │                            │
92       │0   │ Set to 1 enables checking  │
93       │    │ the reference tag          │
94       └────┴────────────────────────────┘
95
96       -m <appmask>, --app-tag-mask=<appmask>
97           App Tag Mask for Protection Information
98
99       -a <apptag>, --app-tag=<apptag>
100           App Tag for Protection Information
101
102       -l, --limited-retry
103           Number of limited attempts to media.
104
105       -f, --force-unit-access
106           FUA option to guarantee that data is stored to media.
107
108       -T <type>, --dir-type=<type>
109           Optional directive type. The nvme-cli only enforces the value be in
110           the defined range for the directive type, though the NVMe
111           specifcation (1.3a) defines only one directive, 01h, for write
112           stream idenfiers.
113
114       -S <spec>, --dir-spec=<spec>
115           Optional field for directive specifics. When used with write
116           streams, this value is defined to be the write stream identifier.
117           The nvme-cli will not validate the stream requested is within the
118           controller’s capabilities.
119
120       -D <dsm>, --dsm=<dsm>
121           The optional data set management attributes for this command. The
122           argument for this is the lower 16 bits of the DSM field in a write
123           command; the upper 16 bits of the field come from the directive
124           specific field, if used. This may be used to set attributes for the
125           LBAs being written, like access frequency, type, latency, among
126           other things, as well as yet to be defined types. Please consult
127           the NVMe specification for detailed breakdown of how to use this
128           field.
129
130       -v, --show-cmd
131           Print out the command to be sent.
132
133       -w, --dry-run
134           Do not actually send the command. If want to use --dry-run option,
135           --show-cmd option must be set. Otherwise --dry-run option will be
136           ignored.
137
138       -t, --latency
139           Print out the latency the IOCTL took (in us).
140

EXAMPLES

142       No examples yet.
143

NVME

145       Part of the nvme-user suite
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149NVMe                              04/24/2020                   NVME-COMPARE(1)
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