1SG_VERIFY(8) SG3_UTILS SG_VERIFY(8)
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6 sg_verify - invoke SCSI VERIFY command(s) on a block device
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9 sg_verify [--bpc=BPC] [--count=COUNT] [--dpo] [--help] [--lba=LBA]
10 [--verbose] [--version] [--vrprotect=VRP] DEVICE
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13 Sends one or more SCSI VERIFY commands to DEVICE. It is the 10 byte
14 VERIFY command defined for block devices (see SBC-2 at
15 http://www.t10.org). Verify starts at the logical block address given
16 by the --lba=LBA option and continues for --count=COUNT blocks. No more
17 than --bpc=BPC blocks are verified by each VERIFY command so if neces‐
18 sary multiple VERIFY commands are sent. No news is good news (i.e. if
19 there are no verify errors detected no messages are sent to stderr and
20 the Unix return status is 0).
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23 Arguments to long options are mandatory for short options as well. The
24 options are arranged in alphabetical order based on the long option
25 name.
26 -b, --bpc=BPC
28 where BPC specifies the maximum number of blocks that will be
29 verified by a single SCSI VERIFY command. The default value is
30 128 blocks which equates to 64 KB for a disk with 512 byte
31 blocks. If BPC is less than COUNT then multiple SCSI VERIFY com‐
32 mands are sent to the device. For recent block devices (disks)
33 this value may be constrained by the maximum transfer length
34 field in the block limits VPD page.
35 -c, --count=COUNT
37 where COUNT specifies the number of blocks to verify. The
38 default value is 1 . If COUNT is greater than BPC (or its
39 default value of 128) then multiple SCSI VERIFY commands are
40 sent to the device. The sg_readcap utility can be used to find
41 the maximum number of blocks that a block device (e.g. a disk)
42 has.
43 -d, --dpo
45 disable page out changes the cache retention priority of blocks
46 read on the device's cache to the lowest priority. This means
47 that blocks read by other commands are more likely to remain in
48 the device's cache.
49 -h, --help
51 output the usage message then exit.
52 -l, --lba=LBA
54 where LBA specifies the logical block address of the first block
55 to start the verify operation. LBA is assumed to be decimal
56 unless prefixed by '0x' or a trailing 'h' (see below). The
57 default value is 0 (i.e. the start of the device).
58 -v, --verbose
60 increase the level of verbosity, (i.e. debug output).
61 -V, --version
63 print the version string and then exit.
64 -P, --vrprotect=VRP
66 where VRP is the value in the vrprotect field in the VERIFY com‐
67 mand cdb. It must be a value between 0 and 7 inclusive. The
68 default value is zero.
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71 Various numeric arguments (e.g. LBA) may include multiplicative suf‐
72 fixes or be given in hexadecimal. See the "NUMERIC ARGUMENTS" section
73 in the sg3_utils(8) man page.
74 The amount of error correction and the number of retries attempted
76 before a block is considered defective are controlled in part by the
77 Verify Error Recovery mode page. A note in the SBC-2 (draft) standard
78 advises that to minimize the number of checks (and hence have the most
79 "sensitive" verify check) do the following in that mode page. Set the
80 EER bit to 0, the PER bit to 1, the DTE bit to 1, the DCR bit to 1, the
81 verify retry count to 0 and the verify error recovery timeout to 0.
82 Mode pages can be modified with the sginfo utility.
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85 The exit status of sg_verify is 0 when it is successful. Otherwise see
86 the sg3_utils(8) man page.
87
89 Written by Douglas Gilbert.
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92 Report bugs to <dgilbert at interlog dot com>.
93
95 Copyright © 2004-2009 Douglas Gilbert
96 This software is distributed under a FreeBSD license. There is NO war‐
97 ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
98 POSE.
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101 sginfo(sg3_utils), sg_modes(sg3_utils), sg_readcap(sg3_utils),
102 sg_inq(sg3_utils)
103sg3_utils-1.27 March 2009 SG_VERIFY(8)