sg_logs - access log pages with SCSI LOG SENSE command
sg_logs [--all] [--brief] [--control=PC] [--help] [--hex] [--list]
[--maxlen=LEN] [--name] [--page=PG[,SPG]] [--paramp=PP] [--pcb] [--ppc]
[--raw] [--reset] [--select] [--sp] [--temperature] [--transport]
[--verbose] [--version] DEVICE
sg_logs [-a] [-A] [-b] [-c=PC] [-h] [-H] [-l] [-L] [-m=LEN] [-n]
[-p=PG[,SPG]] [-paramp=PP] [-pcb] [-ppc] [-r] [-select] [-sp] [-t] [-T]
[-v] [-V] [-?] DEVICE
This utility sends a SCSI LOG SENSE command to the DEVICE and then
outputs the response. The LOG SENSE command is used to fetch log pages.
Known log pages are decoded by default. When the --reset and/or
--select option is given then a SCSI LOG SELECT command is issued to
In SPC-4 revision 5 a subpage code was introduced to both the LOG SENSE
and LOG SELECT command. At the same time a page code field was
introduced to the to the LOG SELECT command. The log subpage code can
range from 0 to 255 (0xff) inclusive. The subpage code value 255 can be
thought of as a wildcard.
This utility supports two command line syntaxes, the preferred one is
shown first in the synopsis and explained in this section. A later
section on the old command line syntax outlines the second group of
Arguments to long options are mandatory for short options as well.
outputs all the log pages supported by the device. This requires
a two stage process: first the "supported log pages" log page is
fetched, then for each entry in the response, the corresponding
log page is fetched and displayed. When used twice (e.g. ’-aa’)
all log pages and subpages are fetched.
shorten the amount of output for some log pages. For example the
Tape Alert log page only outputs parameters whose flags are set
when --brief is given.
accepts 0, 1, 2 or 3 for the PC argument:
0 : current threshold values
1 : current cumulative values
2 : default threshold values
3 : default cumulative values
The default value is 1 (i.e. current cumulative values).
print out the usage message then exit.
The default action is to decode known mode page numbers (and
subpage numbers) into text. When this option is used once, the
response is output in hexadecimal.
lists the names of all logs sense pages supported by this
device. This is done by reading the "supported log pages" log
page. When used twice (e.g. ’-ll’) lists the names of all logs
sense pages and subpages supported by this device. There is a
list of common log page codes below.
sets the "allocation length" field in the LOG SENSE cdb. The is
the maximum length in bytes that the response will be. Without
this option (or LEN equal to 0) this utility first fetches the 4
byte response then does a second access with the length
indicated in the first (4 byte) response. Negative values and 1
for LEN are not accepted. Responses can be quite large (e.g. the
background scan results log page) and this option can be used to
limit the amount of information returned.
decode some log pages into ’name=value’ entries, one per line.
The name contains no space and may be abbreviated and the value
is decimal unless prefixed by ’0x’. Nesting is indicated by
leading spaces. This form is meant to be relatively easy to
switch to older style options.
log page code to access. PG is expected to be a decimal number
between 0 and 63 inclusive. A hexadecimal number can be
specified by a leading "0x" or a trailing "h". Common log page
codes are listed below. Optionally SPG, a subpage code, can be
given. SPG is expected to be a decimal number between 0 and 255
PP is the parameter pointer value to place in a field of that
name in the LOG SENSE cdb. A decimal number in the range 0 to
65535 (0xffff) is expected. When a value greater than 0 is given
the --ppc option should be selected. The default value is 0.
show Parameter Control Byte settings (only relevant when log
parameters being output in ASCII).
sets the Parameter Pointer Control (PPC) bit in the LOG SENSE
cdb. Default is 0 (i.e. cleared).
output the response in binary to stdout. Error messages and
warnings are output to stderr.
use SCSI LOG SELECT command (PCR bit set) to reset the all log
pages (or the given page). [SPC-4 (rev 6) doesn’t say that a
given log (sub)page can be reset yet.] Exactly what is reset
depends on the accompanying SP bit (i.e. --sp option which
defaults to 0) and the PC ("page control") value (which defaults
to 1). Supplying this option implies the --select option as
well. This option seems to clear error counter log pages but
leaves pages like self-test results, start-stop cycle counter
and temperature log pages unaffected. This option may be
required to clear log pages if a counter reaches its maximum
value since the log page in which the counter is found will
remain "stuck" until something is done.
use a LOG SELECT command. The default action (i.e. when neither
this option nor --reset is given) is to do a LOG SENSE command.
When this option is given, the SP bit (i.e. --sp option which
defaults to 0), the PC ("page control") value (which defaults to
1) and the PCR bit (i.e. --reset option which defaults to 0)
are placed in the LOG SELECT cdb. At some stage the log page and
subpage options may also be active [but SPC-4 (rev 6) doesn’t
sets the Saving Parameters (SP) bit. Default is 0 (i.e.
cleared). When set this instructs the device to store the
current log page parameters (as indicated by the DS and TSD
parameter codes) in some non-volatile location. Hence the log
parameters will be preserved across power cycles. This option is
typically not needed, especially if the GLTSD flag is clear in
the control mode page as this instructs the device to
periodically save all saveable log parameters to non-volatile
outputs the temperature. First looks in the temperature log page
and if that is not available tries the Informational Exceptions
log page which may also have the current temperature (especially
on older disks).
outputs the transport (’Protocol specific port’) log page.
Equivalent to setting ’--page=18h’.
increase level of verbosity.
print out version string then exit.
This utility will usually do a double fetch of log pages with the SCSI
LOG SENSE command. The first fetch requests a 4 byte response (i.e.
place 4 in the "allocation length" field in the cdb). From that
response it can calculate the actual length of the response which is
what it asks for on the second fetch. This is typical practice in SCSI
and guaranteed to work in the standards. However some older devices
don’t comply. For those devices using the --maxlen=LEN option will do a
single fetch. A value of 252 should be a safe starting point.
Various log pages hold information error rates, device temperature,
start stop cycles since device produced and the results of the last 20
self tests. Self tests can be initiated by the sg_senddiag(8) utility.
The smartmontools package provides much of the information found with
sg_logs in a form suitable for monitoring the health of SCSI disks and
Here is a list of log pages that are decoded by this utility. [The code
values can be given to ’--page=’ as is, with a trailing "h" instead of
the leading "0x", or as their decimal equivalents.]:
0x0 Supported log pages
0x0,0xff Supported log pages and subpages
0x1 Buffer overrun/underrun
0x2 Write error counter
0x3 Read error counter
0x4 Read reverse error counter
0x5 Verify error counter
0x6 Non-medium error
0x7 Last n error events
0x8 Format status (sbc-2)
0xb Last n deferred errors or asynchronous events
0xc Sequential access device (ssc-2)
0xe Start-stop cycle counter
0x10 Self-test results
0x15 Background scan results (sbc-3)
0x17 Non-volatile cache (sbc-3)
0x18 Protocol specific port (SAS transport)
0x19 General statistics and performance
0x2f Informational exceptions
0x37 Seagate cache (vendor, disk)
0x3e Seagate factory (vendor, disk)
In the 2.4 series of Linux kernels the DEVICE must be a SCSI generic
(sg) device. In the 2.6 series block devices (e.g. SCSI disks and DVD
drives) can also be specified. For example "sg_logs -a /dev/sda" will
work in the 2.6 series kernels.
The exit status of sg_logs is 0 when it is successful. Otherwise see
the sg3_utils(8) man page.
OLDER COMMAND LINE OPTIONS
The options in this section were the only ones available prior to
sg3_utils version 1.23 . In sg3_utils version 1.23 and later these
older options can be selected by either setting the SG3_UTILS_OLD_OPTS
environment variable or using ’--old’ (or ’-O) as the first option.
Options with arguments or with two or more letters can have an extra
’-’ prepended. For example: both ’-pcb’ and ’--pcb’ are acceptable.
-a outputs all the log pages supported by the device. Equivalent
to --all in the main description.
-A outputs all the log pages and subpages supported by the device.
Equivalent to ’--all --all’ in the main description.
-c=PC Equivalent to --control=PC in the main description.
-h suppresses decoding of known log sense pages and prints out the
response in hex instead.
-H same action as ’-h’ in this section and equivalent to --hex in
the main description.
-l lists the names of all logs sense pages supported by this
device. Equivalent to --list in the main description.
-L lists the names of all logs sense pages and subpages supported
by this device. Equivalent to ’--list --list’ in the main
-m=LEN request only LEN bytes of response data. Default is 0 which is
interpreted as all that is available. LEN is decimal unless it
has a leading ’0x’ or trailing ’h’. Equivalent to --maxlen=LEN
in the main description.
-n Equivalent to --name in the main description.
-N switch to the newer style options.
PG is the log page code to access. Should be a hexadecimal
number between 0 and 3f inclusive. If given SPG is the log
subpage code. SPG should be a hexadecimal number between 0 and
ff inclusive. The subpage code of ’ff’ can be thought of as a
PP is the parameter pointer value (in hex) to place in command.
Should be a number between 0 and ffff inclusive.
-pcb show Parameter Control Byte settings (only relevant when log
parameters being output in ASCII).
-ppc sets the Parameter Pointer Control (PPC) bit. Default is 0 (i.e.
-r use SCSI LOG SELECT command (PCR bit set) to reset the all log
pages (or the given page). Equivalent to --reset in the main
use a LOG SELECT command. Equivalent to --select in the main
-sp sets the Saving Parameters (SP) bit. Default is 0 (i.e.
cleared). Equivalent to --sp in the main description.
-t outputs the temperature. Equivalent to --temperature in the main
-T outputs the transport (’Protocol specific port’) log page.
Equivalent to --transport in the main description.
-v increase level of verbosity.
-V print out version string then exit.
-? output usage message then exit.
Written by Doug Gilbert
Report bugs to <dgilbert at interlog dot com>.
Copyright © 2002-2007 Douglas Gilbert
This software is distributed under the GPL version 2. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR