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Serial Attached SCSI (SAS) Linux utilities

Project description

sasutils is a set of command-line tools and a Python library to ease the administration of Serial Attached SCSI (SAS) fabrics. Supported Python Versions License

sasutils command-line tools

  • sas_counters
  • sas_devices
  • sas_discover
  • ses_report

Also, two “zeroconf” udev scripts for use in udev rules that create friendly device aliases using SES-2 subenclosure nicknames.

  • sas_mpath_snic_alias
  • sas_sd_snic_alias


While sasutils gets most of the system data from sysfs (/sys), sg_ses (available in sg3_utils or sg3-utils) and smp_discover (available in smp_utils or smp-utils) are required for some SES features to work.


sas_counters reports SAS/SES/SD I/O and phy error counters and provides SAS topology information in an output suitable for Carbon/Graphite. This command also supports SES-2 nicknames as seen in the example below (io1-sassw1 is the nickname of a SAS switch and io1-jbod1-0 is the nickname of a JBOD SIM).

$ sas_counters
oak-io1-s1.SAS9300-8e.0x500605b00ab01234.Switch184.io1-sassw1.JB4602_SIM_0.io1-jbod1-0.bays.41.ST8000NM0075.0x5000c50084c79876.ioerr_cnt 2 1487457378
oak-io1-s1.SAS9300-8e.0x500605b00ab01234.Switch184.io1-sassw1.JB4602_SIM_0.io1-jbod1-0.bays.41.ST8000NM0075.0x5000c50084c79876.iodone_cnt 7154904 1487457378
oak-io1-s1.SAS9300-8e.0x500605b00ab01234.Switch184.io1-sassw1.JB4602_SIM_0.io1-jbod1-0.bays.41.ST8000NM0075.0x5000c50084c79876.iorequest_cnt 7154906 1487457378
oak-io1-s1.SAS9300-8e.0x500605b00ab05678.Switch184.io1-sassw2.phys.15.invalid_dword_count 5 1487457378
oak-io1-s1.SAS9300-8e.0x500605b00ab05678.Switch184.io1-sassw2.phys.15.loss_of_dword_sync_count 1 1487457378
oak-io1-s1.SAS9300-8e.0x500605b00ab05678.Switch184.io1-sassw2.phys.15.phy_reset_problem_count 0 1487457378
oak-io1-s1.SAS9300-8e.0x500605b00ab05678.Switch184.io1-sassw2.phys.15.running_disparity_error_count 1 1487457378


Display SAS topology. By default, sas_discover tries to fold common devices (like disks). Use -v, -vv or -vvv and --addr to display more details.

$ sas_discover -v
|--host35 SAS9300-8e
|  `--8x--expander-35:0 ASTEK
|         |--1x--end_device-35:0:0
|         |      `--enclosure io1-sassw1 ASTEK
|         `--4x--expander-35:1 QCT
|            |-- 60 x end_device -- disk
|            `--  1 x end_device -- enclosure io1-jbod1-0 QCT
`--host36 SAS9300-8e
   `--8x--expander-36:0 ASTEK
          |      `--enclosure io1-sassw2 ASTEK
          `--4x--expander-36:1 QCT
             |-- 60 x end_device -- disk
             `--  1 x end_device -- enclosure io1-jbod1-1 QCT


Zeroconf tool that scans SAS devices and resolves associated enclosures. Useful to quickly check cabling and hardware setup.

When used with -v, sas_devices will also display all disk devices with serial numbers.

The following example shows a proper detection of a 60-disk JBOD with 2 SIMs (an “enclosure group”).

$ sas_devices
Found 2 SAS hosts
Found 4 SAS expanders
Found 1 enclosure groups
Enclosure group: [io1-jbod1-0][io1-jbod1-1]
NUM         VENDOR        MODEL    REV  PATHS
 60 x      SEAGATE ST8000NM0075   E002      2
Total: 60 block devices in enclosure group


SES status and environmental metrics.

Used with -c, this command will find all enclosures and then use SES-2 nicknames and use sg_ses to output results suitable for Carbon/Graphite.

$ ses_report -c --prefix=datacenter.stanford
datacenter.stanford.io1-sassw1.Cooling.Left_Fan.speed_rpm 19560 1476486766
datacenter.stanford.io1-sassw1.Cooling.Right_Fan.speed_rpm 19080 1476486766
datacenter.stanford.io1-sassw1.Cooling.Center_Fan.speed_rpm 19490 1476486766

Use -s to get the status of all detected SES Element Descriptors.

# ses_report -s --prefix=datacenter.stanford | grep SIM
datacenter.stanford.io1-jbod1-0.Enclosure_services_controller_electronics.SIM_00 OK
datacenter.stanford.io1-jbod1-0.Enclosure_services_controller_electronics.SIM_01 OK
datacenter.stanford.io1-jbod1-0.SAS_expander.SAS_Expander_SIM_0 OK
datacenter.stanford.io1-jbod1-0.SAS_expander.SAS_Expander_ISIM_2 OK
datacenter.stanford.io1-jbod1-0.SAS_expander.SAS_Expander_ISIM_0 OK
datacenter.stanford.io1-jbod1-1.Enclosure_services_controller_electronics.SIM_00 OK
datacenter.stanford.io1-jbod1-1.Enclosure_services_controller_electronics.SIM_01 OK
datacenter.stanford.io1-jbod1-1.SAS_expander.SAS_Expander_SIM_1 OK
datacenter.stanford.io1-jbod1-1.SAS_expander.SAS_Expander_ISIM_3 OK
datacenter.stanford.io1-jbod1-1.SAS_expander.SAS_Expander_ISIM_1 OK


ses_report requires a recent version of sg3_utils and won’t work with the version shipped with CentOS 6 for example.


Generate udev aliases using the SES-2 subenclosure nickname and bay identifier of each device.

For example, add the following to your udev rules:

KERNEL=="sd*", PROGRAM="/usr/bin/sas_sd_snic_alias %k", SYMLINK+="%c"

This should generate udev aliases made of the device subenclosure nickname followed by the bay identifier. In the following case, io1-jbod1-0 is the subenclosure nickname (here SIM 0 of JBOD #1).

$ ls -l /dev/io1-jbod1-0-bay26
lrwxrwxrwx 1 root root 4 Oct 14 21:00 /dev/io1-jbod1-0-bay26 -> sdab


Use sg_ses –nickname=… to define SES-2 subenclosure nicknames.


This utility is very similar to sas_sd_snic_alias but only accepts device-mapper devices. Add the following line to your udev rules:

KERNEL=="dm-[0-9]*", PROGRAM="/usr/bin/sas_mpath_snic_alias %k", SYMLINK+="mapper/%c"

This will result in useful symlinks.

$ ls -l /dev/mapper/io1-jbod1-bay26
lrwxrwxrwx 1 root root 8 Oct 14 21:00 /dev/mapper/io1-jbod1-bay26 -> ../dm-31


For sas_mpath_snic_alias to work with a JBOD having two SIMs, both enclosure nicknames should have a common prefix (eg. “myjbodX-“) that will be automatically used.

sasutils Python library

Documentation will be available on the wiki.

  • the following example will list all SAS hosts (controllers) found in sysfs

    from import SASHost
    from sasutils.sysfs import sysfs
    # sysfs is a helper to walk through sysfs (/sys)
    for node in sysfs.node('class').node('sas_host'):
        # Instantiate SASHost with the sas_host sysfs device class
        host = SASHost(node.node('device'))
        # To get its sysfs name, use:
        # To get attributes from scsi_host, use:
        print('  %s' % host.scsi_host.attrs.host_sas_address)
        print('  %s' % host.scsi_host.attrs.version_fw)
  • See also

Author:Stephane Thiell - Stanford Research Computing Center

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