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SG_VERIFY(8) SG3_UTILS SG_VERIFY(8)
NAME
sg_verify - invoke SCSI VERIFY command(s) on a block device
SYNOPSIS
sg_verify [--bpc=BPC] [--count=COUNT] [--dpo] [--help] [--lba=LBA] [--verbose] [--version]
DEVICE
DESCRIPTION
Sends one or more SCSI VERIFY commands to DEVICE. It is the 10 byte VERIFY command defined
for block devices (see SBC-2 at http://www.t10.org). Verify starts at the logical block
address given by the --lba=LBA option and continues for --count=COUNT blocks. No more than
--bpc=BPC blocks are verified by each VERIFY command so if necessary multiple VERIFY com-
mands are sent. No news is good news (i.e. if there are no verify errors detected no mes-
sages are sent to stderr and the Unix return status is 0).
OPTIONS
Arguments to long options are mandatory for short options as well.
-b, --bpc=BPC
where BPC specifies the maximum number of blocks that will be verified by a single
SCSI VERIFY command. The default value is 128 blocks which equates to 64 KB for a
disk with 512 byte blocks. If BPC is less than COUNT then multiple SCSI VERIFY com-
mands are sent to the device. For recent block devices (disks) this value may be
constrained by the maximum transfer length field in the block limits VPD page.
-c, --count=COUNT
where COUNT specifies the number of blocks to verify. The default value is 1 . If
COUNT is greater than BPC (or its default value of 128) then multiple SCSI VERIFY
commands are sent to the device. The sg_readcap utility can be used to find the
maximum number of blocks that a block device (e.g. a disk) has.
-d, --dpo
disable page out changes the cache retention priority of blocks read on the
device's cache to the lowest priority. This means that blocks read by other com-
mands are more likely to remain in the device's cache.
-h, --help
output the usage message then exit.
-l, --lba=LBA
where LBA specifies the logical block address of the first block to start the ver-
ify operation. LBA is assumed to be decimal unless prefixed by '0x' or a trailing
'h' (see below). The default value is 0 (i.e. the start of the device).
-v, --verbose
increase the level of verbosity, (i.e. debug output).
-V, --version
print the version string and then exit.
NOTES
The BPC, COUNT and LBA arguments may be followed by one of these multiplicative suffixes:
c C *1; w W *2; b B *512; k K KiB *1,024; KB *1,000; m M MiB *1,048,576; MB *1,000,000; g
G GiB *1,073,741,824; GB *1,000,000,000; t T TiB *(2**40); TB *(10**12); p P PiB *(2**50)
and PB *(10**15). The "T" and "P" based suffixes can only be used for COUNT and LBA. Also
a suffix of the form "x<n>" multiplies the leading number by <n>.
Alternatively numerical values can be given in hexadecimal preceded by either "0x" or "0X"
(or has a trailing "h" or "H"). When hex numbers are given, multipliers cannot be used.
The amount of error correction and the number of retries attempted before a block is con-
sidered defective are controlled in part by the Verify Error Recovery mode page. A note
in the SBC-2 (draft) standard advises that to minimize the number of checks (and hence
have the most "sensitive" verify check) do the following in that mode page. Set the EER
bit to 0, the PER bit to 1, the DTE bit to 1, the DCR bit to 1, the verify retry count to
0 and the verify error recovery timeout to 0. Mode pages can be modified with the sginfo
utility.
EXIT STATUS
The exit status of sg_verify is 0 when it is successful. Otherwise see the sg3_utils(8)
man page.
AUTHORS
Written by Douglas Gilbert.
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright (C) 2004-2007 Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO warranty; not even for
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
SEE ALSO
sginfo(sg3_utils), sg_modes(sg3_utils), sg_readcap(sg3_utils), sg_inq(sg3_utils)
sg3_utils-1.23 January 2007 SG_VERIFY(8)
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On Apache
Under GNU General Public License
2012-05-26 06:28 @38.107.179.239 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)