1NVME-COMPARE(1) NVMe Manual NVME-COMPARE(1)
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6 nvme-compare - Send an NVMe Compare command, provide results
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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 [--storage-tag<storage-tag> | -g <storage-tag>]
28 [--storage-tag-check | -C]
29 [--force]
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32 The Compare command reads the logical blocks specified by the command
33 from the medium and compares the data read to a comparison data buffer
34 transferred as part of the command. If the data read from the
35 controller and the comparison data buffer are equivalent with no
36 miscompares, then the command completes successfully. If there is any
37 miscompare, the command completes with an error of Compare Failure. If
38 metadata is provided, then a comparison is also performed for the
39 metadata.
40
42 -s <slba>, --start-block=<slba>
43 64-bit address of the first block to access.
44 -c <nlb>, --block-count=<nlb>
46 Number of blocks to be accessed (zero-based).
47 -z <size>, --data-size=<size>
49 Size of data to be compared in bytes.
50 -y <metasize>, --metadata-size=<metasize>
52 Size of metadata to be transferred in bytes.
53 -r <reftag>, --ref-tag=<reftag>
55 Reference Tag for Protection Information
56 -d <data-file>, --data=<data-file>
58 Data file.
59 -M <meta>, --metadata=<meta>
61 Metadata file.
62 -p <prinfo>, --prinfo=<prinfo>
64 Protection Information and check field.
65 +
67 ┌────┬────────────────────────────┐
69 │ │ │
70 │Bit │ Description │
71 ├────┼────────────────────────────┤
72 │ │ │
73 │3 │ PRACT: Protection │
74 │ │ Information Action. When │
75 │ │ set to 1, PI is │
76 │ │ stripped/inserted on │
77 │ │ read/write when the block │
78 │ │ format’s metadata size is │
79 │ │ 8. When set to 0, metadata │
80 │ │ is passes. │
81 ├────┼────────────────────────────┤
82 │ │ │
83 │2:0 │ PRCHK: Protection │
84 │ │ Information Check: │
85 ├────┼────────────────────────────┤
86 │ │ │
87 │2 │ Set to 1 enables checking │
88 │ │ the guard tag │
89 ├────┼────────────────────────────┤
90 │ │ │
91 │1 │ Set to 1 enables checking │
92 │ │ the application tag │
93 ├────┼────────────────────────────┤
94 │ │ │
95 │0 │ Set to 1 enables checking │
96 │ │ the reference tag │
97 └────┴────────────────────────────┘
98 -m <appmask>, --app-tag-mask=<appmask>
100 App Tag Mask for Protection Information
101 -a <apptag>, --app-tag=<apptag>
103 App Tag for Protection Information
104 -l, --limited-retry
106 Number of limited attempts to media.
107 -f, --force-unit-access
109 FUA option to guarantee that data is stored to media.
110 -T <type>, --dir-type=<type>
112 Optional directive type. The nvme-cli only enforces the value be in
113 the defined range for the directive type, though the NVMe
114 specification (1.3a) defines only one directive, 01h, for write
115 stream identifiers.
116 -S <spec>, --dir-spec=<spec>
118 Optional field for directive specifics. When used with write
119 streams, this value is defined to be the write stream identifier.
120 The nvme-cli will not validate the stream requested is within the
121 controller’s capabilities.
122 -D <dsm>, --dsm=<dsm>
124 The optional data set management attributes for this command. The
125 argument for this is the least significant 8 bits of the DSM field
126 in a write command; the most significant 16 bits of the field come
127 from the directive specific field, if used. This may be used to set
128 attributes for the LBAs being written, like access frequency, type,
129 latency, among other things, as well as yet to be defined types.
130 Please consult the NVMe specification for detailed breakdown of how
131 to use this field.
132 -v, --show-cmd
134 Print out the command to be sent.
135 -w, --dry-run
137 Do not actually send the command. If want to use --dry-run option,
138 --show-cmd option must be set. Otherwise --dry-run option will be
139 ignored.
140 -t, --latency
142 Print out the latency the IOCTL took (in us).
143 -g <storage-tag>, --storage-tag=<storage-tag>
145 Variable Sized Expected Logical Block Storage Tag(ELBST).
146 -C, --storage-tag-check
148 This flag enables Storage Tag field checking as part of end-to-end
149 data protection processing.
150 --force
152 Ignore namespace is currently busy and performed the operation even
153 though.
154
156 No examples yet.
157
159 Part of the nvme-user suite
160NVMe 09/29/2023 NVME-COMPARE(1)