sg_logs.8

.TH SG_LOGS "8" "April 2007" "sg3_utils\-1.24" SG3_UTILS
.SH NAME
sg_logs \- access log pages with SCSI LOG SENSE command
.SH SYNOPSIS
.B sg_logs
[\fI\-\-all\fR] [\fI\-\-brief\fR] [\fI\-\-control=PC\fR] [\fI\-\-help\fR]
[\fI\-\-hex\fR] [\fI\-\-list\fR] [\fI\-\-maxlen=LEN\fR] [\fI\-\-name\fR]
[\fI\-\-page=PG[,SPG]\fR] [\fI\-\-paramp=PP\fR] [\fI\-\-pcb\fR]
[\fI\-\-ppc\fR] [\fI\-\-raw\fR] [\fI\-\-reset\fR] [\fI\-\-select\fR]
[\fI\-\-sp\fR] [\fI\-\-temperature\fR] [\fI\-\-transport\fR]
[\fI\-\-verbose\fR] [\fI\-\-version\fR] \fIDEVICE\fR
.PP
.B sg_logs
[\fI\-a\fR] [\fI\-A\fR] [\fI\-b\fR] [\fI\-c=PC\fR] [\fI\-h\fR] [\fI\-H\fR]
[\fI\-l\fR] [\fI\-L\fR] [\fI\-m=LEN\fR] [\fI\-n\fR] [\fI\-p=PG[,SPG]\fR]
[\fI\-paramp=PP\fR] [\fI\-pcb\fR] [\fI\-ppc\fR] [\fI\-r\fR] [\fI\-select\fR]
[\fI\-sp\fR] [\fI\-t\fR] [\fI\-T\fR] [\fI\-v\fR] [\fI\-V\fR] [\fI\-?\fR]
\fIDEVICE\fR
.SH DESCRIPTION
.\" Add any additional description here
.PP
This utility sends a SCSI LOG SENSE command to the \fIDEVICE\fR and then
outputs the response. The LOG SENSE command is used to fetch log pages. Known
log pages are decoded by default. When the \fI\-\-reset\fR and/or
\fI\-\-select\fR option is given then a SCSI LOG SELECT command is issued to
reset parameters.
.PP
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.
.PP
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 options.
.SH OPTIONS
Arguments to long options are mandatory for short options as well.
.TP
\fB\-a\fR, \fB\-\-all\fR
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.
.TP
\fB\-b\fR, \fB\-\-brief\fR
shorten the amount of output for some log pages. For example the Tape
Alert log page only outputs parameters whose flags are set when
\fI\-\-brief\fR is given.
.TP
\fB\-c\fR, \fB\-\-control\fR=\fIPC\fR
accepts 0, 1, 2 or 3 for the \fIPC\fR argument:
.br
  \fB0\fR : current threshold values
.br
  \fB1\fR : current cumulative values
.br
  \fB2\fR : default threshold values
.br
  \fB3\fR : default cumulative values
.br
The default value is 1 (i.e. current cumulative values).
.TP
\fB\-h\fR, \fB\-\-help\fR
print out the usage message then exit.
.TP
\fB\-H\fR, \fB\-\-hex\fR
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.
.TP
\fB\-l\fR, \fB\-\-list\fR
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.
.TP
\fB\-m\fR, \fB\-\-maxlen\fR=\fILEN\fR
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 \fILEN\fR
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 \fILEN\fR 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.
.TP
\fB\-n\fR, \fB\-\-name\fR
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 parse.
.TP
\fB\-O\fR, \fB\-\-old\fR
switch to older style options.
.TP
\fB\-p\fR, \fB\-\-page\fR=\fIPG[,SPG]\fR
log page code to access. \fIPG\fR 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
\fISPG\fR, a subpage code, can be given. \fISPG\fR is expected to be a
decimal number between 0 and 255 inclusive.
.TP
\fB\-P\fR, \fB\-\-paramp\fR=\fIPP\fR
\fIPP\fR 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 \fI\-\-ppc\fR option
should be selected. The default value is 0.
.TP
\fB\-q\fR, \fB\-\-pcb\fR
show Parameter Control Byte settings (only relevant when log parameters
being output in ASCII).
.TP
\fB\-Q\fR, \fB\-\-ppc\fR
sets the Parameter Pointer Control (PPC) bit in the LOG SENSE cdb. Default
is 0 (i.e. cleared).
.TP
\fB\-r\fR, \fB\-\-raw\fR
output the response in binary to stdout. Error messages and warnings are
output to stderr.
.TP
\fB\-R\fR, \fB\-\-reset\fR
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. \fI\-\-sp\fR option which defaults to 0) and the
\fIPC\fR ("page control") value (which defaults to 1). Supplying this option
implies the \fI\-\-select\fR 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.
.TP
\fB\-S\fR, \fB\-\-select\fR
use a LOG SELECT command. The default action (i.e. when neither this option
nor \fI\-\-reset\fR is given) is to do a LOG SENSE command. When this option
is given, the SP bit (i.e. \fI\-\-sp\fR option which defaults to 0), the
\fIPC\fR ("page control") value (which defaults to 1) and the PCR bit (i.e.
\fI\-\-reset\fR 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 say that].
.TP
\fB\-s\fR, \fB\-\-sp\fR
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 locations.
.TP
\fB\-t\fR, \fB\-\-temperature\fR
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).
.TP
\fB\-T\fR, \fB\-\-transport\fR
outputs the transport ('Protocol specific port') log page. Equivalent
to setting '\-\-page=18h'.
.TP
\fB\-v\fR, \fB\-\-verbose\fR
increase level of verbosity.
.TP
\fB\-V\fR, \fB\-\-version\fR
print out version string then exit.
.SH NOTES
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 \fI\-\-maxlen=LEN\fR option will do a single fetch.
A value of 252 should be a safe starting point.
.PP
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
tape drives.
.PP
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.]:
.PP
0x0       Supported log pages
.br
0x0,0xff  Supported log pages and subpages
.br
0x1       Buffer overrun/underrun
.br
0x2       Write error counter
.br
0x3       Read error counter
.br
0x4       Read reverse error counter
.br
0x5       Verify error counter
.br
0x6       Non\-medium error
.br
0x7       Last n error events
.br
0x8       Format status (sbc\-2)
.br
0xb       Last n deferred errors or asynchronous events
.br
0xc       Sequential access device (ssc\-2)
.br
0xd       Temperature
.br
0xe       Start\-stop cycle counter
.br
0x10      Self\-test results
.br
0x15      Background scan results (sbc\-3)
.br
0x17      Non\-volatile cache (sbc\-3)
.br
0x18      Protocol specific port (SAS transport)
.br
0x19      General statistics and performance
.br
0x2f      Informational exceptions
.br
0x37      Seagate cache (vendor, disk)
.br
0x3e      Seagate factory (vendor, disk)
.PP
In the 2.4 series of Linux kernels the \fIDEVICE\fR 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.
.SH EXIT STATUS
The exit status of sg_logs is 0 when it is successful. Otherwise see
the sg3_utils(8) man page.
.SH 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.
.PP
Options with arguments or with two or more letters can have an extra '\-'
prepended. For example: both '\-pcb' and '\-\-pcb' are acceptable.
.TP
\fB\-a\fR
outputs all the log pages supported by the device. 
Equivalent to \fI\-\-all\fR in the main description.
.TP
\fB\-A\fR
outputs all the log pages and subpages supported by the device.
Equivalent to '\-\-all \-\-all' in the main description.
.TP
\fB\-c\fR=\fIPC\fR
Equivalent to \fI\-\-control=PC\fR in the main description.
.TP
\fB\-h\fR
suppresses decoding of known log sense pages and prints out the
response in hex instead.
.TP
\fB\-H\fR
same action as '\-h' in this section and equivalent to \fI\-\-hex\fR in
the main description.
.TP
\fB\-l\fR
lists the names of all logs sense pages supported by this device.
Equivalent to \fI\-\-list\fR in the main description.
.TP
\fB\-L\fR
lists the names of all logs sense pages and subpages supported by this
device. Equivalent to '\-\-list \-\-list' in the main description.
.TP
\fB\-m\fR=\fILEN\fR
request only \fILEN\fR bytes of response data. Default is 0 which is
interpreted as all that is available. \fILEN\fR is decimal unless it has
a leading '0x' or trailing 'h'.  Equivalent to \fI\-\-maxlen=LEN\fR in
the main description.
.TP
\fB\-n\fR
Equivalent to \fI\-\-name\fR in the main description.
.TP
\fB\-N\fR
switch to the newer style options.
.TP
\fB\-p\fR=\fIPG[,SPG]\fR
\fIPG\fR is the log page code to access. Should be a hexadecimal number
between 0 and 3f inclusive. If given \fISPG\fR is the log subpage code.
\fISPG\fR should be a hexadecimal number between 0 and ff inclusive. The
subpage code of 'ff' can be thought of as a wildcard.
.TP
\fB\-paramp\fR=\fIPP\fR
\fIPP\fR is the parameter pointer value (in hex) to place in command.
Should be a number between 0 and ffff inclusive. 
.TP
\fB\-pcb\fR
show Parameter Control Byte settings (only relevant when log parameters
being output in ASCII).
.TP
\fB\-ppc\fR
sets the Parameter Pointer Control (PPC) bit. Default is 0 (i.e. cleared).
.TP
\fB\-r\fR
use SCSI LOG SELECT command (PCR bit set) to reset the all log pages (or
the given page). Equivalent to \fI\-\-reset\fR in the main description.
.TP
\fB\-select\fR
use a LOG SELECT command. Equivalent to \fI\-\-select\fR in the main
description.
.TP
\fB\-sp\fR
sets the Saving Parameters (SP) bit. Default is 0 (i.e. cleared).
Equivalent to \fI\-\-sp\fR in the main description.
.TP
\fB\-t\fR
outputs the temperature. Equivalent to \fI\-\-temperature in the main
description.
.TP
\fB\-T\fR
outputs the transport ('Protocol specific port') log page. Equivalent
to \fI\-\-transport\fR in the main description.
.TP
\fB\-v\fR
increase level of verbosity.
.TP
\fB\-V\fR
print out version string then exit.
.TP
\fB\-?\fR
output usage message then exit.
.SH AUTHOR
Written by Doug Gilbert
.SH "REPORTING BUGS"
Report bugs to <dgilbert at interlog dot com>.
.SH COPYRIGHT
Copyright \(co 2002\-2007 Douglas Gilbert
.br
This software is distributed under the GPL version 2. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
.SH "SEE ALSO"
.B smartctl(smartmontools), sg_senddiag(8)