lsscsi(8) - phpMan

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 every-
thing. 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 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"
directory. This "match by major and minor" will allow devices that have been given a dif-
ferent 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 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 "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 Archi-
tecture 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 initia-
tor, 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 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 informa-
tion 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 tar-
get 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 associ-
ated 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 option is
given then only "iscsi:" is output on the summary line.

For Serial Attached SCSI the SAS address of the target port (or initiator port if --hosts
option is also given) is output. This will be a naa-5 address. For SAS HBAs and SAS tar-
gets (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 (usually 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 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 logi-
cal 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 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 inte-
ger. 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 LSS-
CSI_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_LUN-
HEX_OPT=2 lsscsi' 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 driv-
ers (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 some-
thing 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 CONFIG_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 (C) 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.