path by replacing the device identifier with the identifier from the sg or st device. For example, a
command executed on
pfo3
will report information for the device at
sg3
and
st3
.
Viewing the current driver revision
The driver revision number indicates the build date of the driver and can be viewed by running:
cat /proc/scsi/sg/version
Viewing device status
You can view the status of a device that is controlled by the failover driver by reading a file in the /sys file
system. For example, to see the path status for /dev/sg3:
cat /sys/class/pfo/pfo3/paths
Terms
active_drive
A path to a tape library via an advanced path failover active drive.
down
The driver is aware of this path, but if the driver attempted to use this path at this time it would fail and
another path would need to be chosen.
last
The path that the driver was most recently able to successfully perform a SCSI command on. This is
probably the path that will be used next. There are no
/dev
files open to this device.
open
The path that the driver was most recently able to successfully perform a SCSI command on. This is
probably the path that will be used next. There is at least one
/dev
file open to this device.
prefer
The driver will attempt to send the commands on this path after the next device file open() call. This
path will override the last known good path.
session_key
The identifier number of the open session, in hexadecimal.
wwnn
World-wide node name of the device.
wwpn
World-wide port name of the Fibre Channel port on the device.
Example paths
# cat /sys/class/pfo/*/paths
sg=/dev/sg0 st=/dev/st0 wwnn=50014382c6c2f001 type=tape
0:0:3:0 up - - wwpn=50014382c6c2f003
0:0:0:0 up - - wwpn=50014382c6c2f002
1:0:0:0 up - - wwpn=50014382c6c2f002
1:0:2:0 up - - wwpn=50014382c6c2f003
sg=/dev/sg1 st=none wwnn=50014382c6c2f800 type=changer session_key=cae82d14
0:0:3:1 up - - active_drive
0:0:0:1 up last prefer active_drive
0:0:1:1 up - - -
0:0:2:1 up - - -
Viewing the current driver revision
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