lsscsi man page on Slackware
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lsscsi(8) LSSCSI lsscsi(8)
NAME
lsscsi - list SCSI devices (or hosts) and their attributes
SYNOPSIS
lsscsi [--classic] [--device] [--generic] [--help] [--hosts] [--kname]
[--list] [--lunhex] [--long] [--protection] [--protmode] [--scsi_id]
[--size] [--sysfsroot=PATH] [--transport] [--verbose] [--version]
[--wwn] [H:C:T:L]
DESCRIPTION
Uses information in sysfs (Linux kernel series 2.6 and later) to list
SCSI devices (or hosts) currently attached to the system. Options can
be used to control the amount and form of information provided for each
device.
If a H:C:T:L argument is given then it acts as a filter and only
devices that match it are listed. The colons don't have to be present,
and '-', '*', '?' or missing arguments at the end are interpreted as
wildcards. The default is '*:*:*:*' which means to match everything.
Any filter string using '*' of '?' should be surrounded by single or
double quotes to stop shell expansions. If '-' is used as a wildcard
then the whole filter argument should be prefixed by '-- ' to tell this
utility there are no more options on the command line to be inter‐
preted. A leading '[' and trailing ']' are permitted (e.g. '[1:0:0]'
matches all LUNs on 1:0:0). May also be used to filter --hosts in which
case only the H is active and may be either a number or in the form
"host<n>" where <n> is a host number.
By default in this utility device node names (e.g. "/dev/sda" or
"/dev/root_disk") are obtained by noting the major and minor numbers
for the listed device obtained from sysfs (e.g. the contents of
"/sys/block/sda/dev") and then looking for a match in the "/dev" direc‐
tory. This "match by major and minor" will allow devices that have been
given a different name by udev (for example) to be correctly reported
by this utility.
In some situations it may be useful to see the device node name that
Linux would produce by default, so the --kname option is provided. An
example of where this may be useful is kernel error logs which tend to
report disk error messages using the disk's default kernel name.
OPTIONS
Arguments to long options are mandatory for short options as well. The
options are arranged in alphabetical order based on the long option
name.
-c, --classic
The output is similar to that obtained from 'cat
/proc/scsi/scsi'
-d, --device
After outputting the (probable) SCSI device name the device node
major and minor numbers are shown in brackets (e.g.
"/dev/sda[8:0]").
-g, --generic
Output the SCSI generic device file name. Note that if the sg
driver is a module it may need to be loaded otherwise '-' may
appear.
-h, --help
Output the usage message and exit.
-H, --hosts
List the SCSI hosts currently attached to the system. If this
option is not given then SCSI devices are listed.
-k, --kname
Use Linux default algorithm for naming devices (e.g. block major
8, minor 0 is "/dev/sda") rather than the "match by major and
minor" in the "/dev" directory as discussed above.
-L, --list
Output additional information in <attribute_name>=<value> pairs,
one pair per line preceded by two spaces. This option has the
same effect as '-lll'.
-l, --long
Output additional information for each SCSI device (host). Can
be used multiple times for more output in which case the shorter
option form is more convenient (e.g. '-lll'). When used three
times (i.e. '-lll') outputs SCSI device (host) attributes one
per line; preceded by two spaces; in the form
"<attribute_name>=<value>".
-x, --lunhex
when this option is used once the LUN in the tuple (at the start
of each device line) is shown in "T10" format which is up to 16
hexadecimal digits. It is prefixed by "0x" to distinguish the
LUN from the decimal value shown in the absence of this option.
Also hierarchal LUNs are shown with a "_" character separating
the levels. For example the two level LUN: 0x0355006600000000
will appear as 0x0355_0066. If this option is given twice (e.g.
using the short form: '-xx') then the full 16 hexadecimal digits
are shown for each LUN, prefixed by "0x".
-p, --protection
Output target (DIF) and initiator (DIX) protection types.
-P, --protmode
Output effective protection information mode for each disk
device.
-i, --scsi_id
outputs the udev derived matching id found in
/dev/disk/by-id/scsi* . This is only for disk (and disk like)
devices. If no match is found then "dm-uuid-mpath*" and "usb*"
are searched in the same directory. If there is still no match
then the /sys/class/block/<disk>/holders directory is searched.
The matching id is printed following the device name (e.g.
/dev/sdc) and if there is no match "-" is output.
-s, --size
Print disk capacity in human readable form.
-t, --transport
Output transport information. This will be a target related
information or, if --hosts is given, initiator related informa‐
tion. When used without --list, a name or identifier (or both)
are output on a single line, usually prefixed by the type of
transport. For devices this information replaces the normal ven‐
dor, product and revision strings. When the --list option is
also given then additionally multiple lines of
attribute_name=value pairs are output, each indented by two spa‐
ces. See the section on transports below.
-v, --verbose
outputs directory names where information is found. Use multiple
times for more output.
-V, --version
outputs version information then exits.
-w, --wwn
outputs the WWN for disks instead of manufacturer, model and
revision (or instead of transport information). The World Wide
Name (WWN) is typically 64 bits long (16 hex digits) but could
be up to 128 bits long. To indicate the WWN is hexadecimal, it
is prefixed by "0x".
-y, --sysfsroot=PATH
assumes sysfs is mounted at PATH instead of the default '/sys' .
If this option is given PATH should be an absolute path (i.e.
start with '/').
TRANSPORTS
This utility lists SCSI devices which are known as logical units (LU)
in the SCSI Architecture Model (ref: SAM-4 at http://www.t10.org) or
hosts when the --hosts option is given. A host is called an initiator
in SAM-4. A SCSI command travels out via an initiator, across some
transport to a target and then onwards to a logical unit. A target
device may contain several logical units. A target device has one or
more ports that can be viewed as transport end points. Each FC and SAS
disk is a single target that has two ports and contains one logical
unit. If both target ports on a FC or SAS disk are connected and visi‐
ble to a machine, then lsscsi will show two entries. Initiators (i.e.
hosts) also have one or more ports and some HBAs in Linux have a host
entry per initiator port while others have a host entry per initiator
device.
When the --transport option is given for devices (i.e. --hosts not
given) then most of the information produced by lsscsi is associated
with the target, or more precisely: the target port, through which SCSI
commands pass that access a logical unit.
Typically this utility provides one line of output per "device" or
host. Significantly more information can be obtained by adding the
--list option. When used together with the --transport option, after
the summary line, multiple lines of transport specific information in
the form "<attribute_name>=<value>" are output, each indented by two
spaces. Using a filter argument will reduce the volume of output if a
lot of devices or hosts are present.
The transports that are currently recognized are: IEEE 1394, ATA, FC,
iSCSI, SAS, SATA, SPI and USB.
For IEEE 1394 (a.k.a. Firewire and "SBP" when storage is involved), the
EUI-64 based target port name is output when --transport is given, in
the absence of the --hosts option. When the --hosts option is given
then the EUI-64 initiator port name is output. Output on the summary
line specific to the IEEE 1394 transport is prefixed by "sbp:".
to detect ATA and SATA a crude check is performed on the driver name
(after the checks for other transports are exhausted). Based on the
driver name either ATA or SATA transport type is chosen. Output on the
summary line is either "ata:" or "sata:". No other attributes are
given. Most device and hosts flagged as "ata:" will use the parallel
ATA transport (PATA).
For Fibre Channel (FC) the port name and port identifier are output
when --transport is given. In the absence of the --hosts option these
ids will be for the target port associated with the device (logical
unit) being listed. When the --hosts option is given then the ids are
for the initiator port used by the host. Output on the summary line
specific to the FC transport is prefixed by "fc:". If FCoE (over Eth‐
ernet) is detected the prefix is changed to "fcoe:".
For iSCSI the target port name is output when --transport is given, in
the absence of the --hosts option. This is made up of the iSCSI name
and the target portal group tag. Since the iSCSI name starts with "iqn"
no further prefix is used. When the --hosts option is given then only
"iscsi:" is output on the summary line.
For Serial Attached SCSI the SAS address of the target port (or initia‐
tor port if --hosts option is also given) is output. This will be a
naa-5 address. For SAS HBAs and SAS targets (such as SAS disks and tape
drives) the SAS address will be world wide unique. For SATA disks
attached to a SAS expander, the expander provides the SAS address by
adding a non zero value to its (i.e. the expander's) SAS address (e.g.
expander_sas_address + phy_id + 1). SATA disks directly attached to SAS
HBAs seem to have an indeterminate SAS address. Output on the summary
line specific to the SAS transport is prefixed by "sas:".
For the SCSI Parallel Interface (SPI) the target port identifier (usu‐
ally a number between 0 and 15 inclusive) is output when --transport is
given, in the absence of the --hosts option. When the --hosts option is
given then only "spi:" is output on the summary line.
When a USB transport is detected, the summary line will contain "usb:"
followed by a USB device name. The USB device name has the form
"<b>-<p1>[.<p2>[.<p3>]]:<c>.<i>" where <b> is the USB bus number, <p1>
is the port on the host. <p2> is a port on a host connected hub, if
present. If needed <p3> is a USB hub port closer to the USB storage
device. <c> refers to the configuration number while <i> is the inter‐
face number. There is a separate SCSI host for each USB (SCSI) target.
A USB SCSI target may contain multiple logical units. Thus the same
"usb: <device_name>" string appears for a USB SCSI host and all logical
units that belong to the USB SCSI target associated with that USB SCSI
host.
LUNS
For historical reasons and as used by several other Unix based Operat‐
ing Systems, Linux uses a tuple of integers to describe (a path to) a
SCSI device (also know as a Logical Unit (LU)). The last element of
that tuple is the so-called Logical Unit Number (LUN). And originally
in SCSI a LUN was an integer, at first 3 bits long, then 8 then 16
bits. SCSI LUNs today (SAM-5 section 4.7) are 64 bits but SCSI stan‐
dards now consider a LUN to be an array of 8 bytes.
Up until 2013, Linux mapped SCSI LUNs to a 32 bit integer by taking the
first 4 bytes of the SCSI LUN and ignoring the last 4 bytes. Linux
treated the first two bytes of the SCSI LUN as a unit (a word) and it
became the least significant 16 bits in the Linux LUN integer. The next
two bytes of the SCSI LUN became the upper 16 bits in the Linux LUN
integer. The rationale for this was to keep commonly used LUNs small
Linux LUN integers. The most common LUN (by far) in SCSI LUN (hex)
notation is 00 00 00 00 00 00 00 00 and this becomes the Linux LUN
integer 0. The next most common LUN is 00 01 00 00 00 00 00 00 and this
becomes the Linux LUN integer 1.
In 2013 it is proposed to increase Linux LUNs to a 64 bit integer by
extending the mapping outlined above. In this case all information that
is possible to represent in a SCSI LUN is mapped a Linux LUN (64 bit)
integer. And the mapping can be reversed without losing information.
This version of the utility supports both 32 and 64 bit Linux LUN inte‐
gers. By default the LUN shown at the end of the tuple commencing each
line is a Linux LUN as a decimal integer. When the --lunhex option is
given then the LUN is in SCSI LUN format with the 8 bytes run together,
with the output in hexadecimal and prefixed by '0x'. The LUN is decoded
according to SAM-5's description and trailing zeros (i.e. digits to the
right) are not shown. So LUN 0 (i.e. 00 00 00 00 00 00 00 00) is shown
as 0x0000 and LUN 65 (i.e. 00 41 00 00 00 00 00 00) is shown as 0x0041.
If the --lunhex option is given twice then the full 64 bits (i.e. 16
hexadecimal digits) are shown.
If the --lunhex option is not given on the command line then the envi‐
ronment variable LSSCSI_LUNHEX_OPT is checked. If LSSCSI_LUNHEX_OPT is
present then its associated value becomes the number of times the
--lunhex is set internally. So, for example, 'LSSCSI_LUNHEX_OPT=2 lss‐
csi' and 'lsscsi -xx' are equivalent.
EXAMPLES
Information about this utility including examples can also be found at:
http://sg.danny.cz/scsi/lsscsi.html .
NOTES
Information for this command is derived from the sysfs file system,
which is assumed to be mounted at /sys unless specified otherwise by
the user. SCSI (pseudo) devices that have been detected by the SCSI
mid level will be listed even if the required upper level drivers (i.e.
sd, sr, st, osst or ch) have not been loaded. If the appropriate upper
level driver has not been loaded then the device file name will appear
as '-' rather than something like '/dev/st0'. Note that some devices
(e.g. scanners and medium changers) do not have a primary upper level
driver and can only be accessed via a SCSI generic (sg) device name.
Generic SCSI devices can also be accessed via the bsg driver in Linux.
By default, the bsg driver's device node names are of the form
'/dev/bsg/H:C:T:L'. So, for example, the SCSI device shown by this
utility on a line starting with the tuple '6:0:1:2' could be accessed
via the bsg driver with the '/dev/bsg/6:0:1:2' device node name.
lsscsi version 0.21 or later is required to correctly display SCSI
devices in Linux kernel 2.6.26 (and possibly later) when the CON‐
FIG_SYSFS_DEPRECATED_V2 kernel option is not defined.
AUTHOR
Written by Doug Gilbert
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright © 2003-2013 Douglas Gilbert
This software is distributed under the GPL version 2. There is NO war‐
ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
POSE.
SEE ALSO
lspci lsusb
lsscsi-0.27 March 2013 lsscsi(8)
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