lsscsi - list SCSI devices (or hosts) and their attributes
] [ --hosts
] [ --long
] [ --verbose
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 interpreted. 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
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" directory. 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.
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
- -d, --device
- After outputting the (probable) SCSI device name the device
node major and minor numbers are shown in brackets (e.g.
- -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
- -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
- -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
- -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
- -P, --protmode
- Output effective protection information mode for each disk
- -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 information.
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 vendor, 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
spaces. 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
- -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 '/').
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
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 visible 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
When the --transport
option is given for devices (i.e. --hosts
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
option. When used together with the --transport
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
in the absence of the --hosts
option. When the --hosts
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
For Fibre Channel (FC) the port name and port identifier are output when
is given. In the absence of the --hosts
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 Ethernet) 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
given then only "iscsi:" is output on the summary line.
For Serial Attached SCSI the SAS address of the target port (or initiator port
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
For the SCSI Parallel Interface (SPI) the target port identifier (usually a
number between 0 and 15 inclusive) is output when --transport
in the absence of the --hosts
option. When the --hosts
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
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 interface 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.
For historical reasons and as used by several other Unix based Operating
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 standards 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 integers. 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
environment variable LSSCSI_LUNHEX_OPT is checked. If LSSCSI_LUNHEX_OPT is
present then its associated value becomes the number of times the
is set internally. So, for example, 'LSSCSI_LUNHEX_OPT=2
lsscsi' and 'lsscsi -xx' are equivalent.
Information about this utility including examples can also be found at:
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/
'. 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 CONFIG_SYSFS_DEPRECATED_V2
kernel option is not defined.
Written by Doug Gilbert
Report bugs to <dgilbert at interlog dot com>.
Copyright © 2003-2013 Douglas Gilbert
This software is distributed under the GPL version 2. There is NO warranty; not
even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.