sas_discover - Man Page

display Serial Attached SCSI (SAS) topology


sas_discover [-h] [--verbose] [--addr] [--devices] [--counters]


sas_discover displays the SAS topology from the host initiator(s), through any SAS expanders up to the SAS targets. Each link usually represents a SAS port connection, whether it uses one or more PHYs.  The number of PHYs per port is explicitly shown if greater than one (eg. "--4x--" for a 4-PHY wide port). Please note that by default, sas_discover tries to fold common devices (like disks), like in the example below:

-- 60 x end_device -- disk

60 x 1-PHY links, each connected to a SAS end_device target of SCSI type disk

Host initiators, expanders and end devices are labelled with the same name used in sysfs. If -v is provided, more descriptive information will be displayed, but the topology will stay folded whenever possible. sas_discover -v will also print SES-2 subenclosure nicknames, which are useful to identify JBODs/SIMs and external SAS switches connected to the topology.

Use -vv to unfold the topology and display more information (eg. model, size, bay identifier in enclosure).

Use -vvv to display additional low-level information for each SAS end device.

Add --addr to also display the SAS address for each SAS component found in the topology.


optional arguments:
-h, --help

show this help message and exit

--verbose, -v

Verbosity level, repeat multiple times!


Print SAS addresses


Print associated devices


Print I/O counters

Exit Status

An exit status of zero indicates success of the command, and failure otherwise.

See Also

sas_counters(1), sas_devices(1), ses_report(1)

Bug Reports

Use the following URL to submit a bug report or feedback:


Stephane Thiell <>

Referenced By

sas_counters(1), sas_devices(1), ses_report(1).

2023-10-01 0.5.0 sasutils