User's Manual

Legacy reservations:
echo legacy > /sys/class/pfo/pfo4/ctrl
Persistent reservations:
echo persistent > /sys/class/pfo/pfo4/ctrl
Prevent allow medium removal conditions:
echo prevent > /sys/class/pfo/pfo4/ctrl
Debug output control
You can control the level of debug messages being sent to the console.
The default output level is minimum.
To minimize the level of debug messages:
echo 0x0000 > /sys/bus/scsi/drivers/pfo/debug_flag
To maximize the level of debug messages:
echo 0xffff > /sys/bus/scsi/drivers/pfo/debug_flag
NOTE: Increased debug logging will affect performance.
The definition of all of the bits in the value is beyond the scope of this document.
Reading the trace log
The failover driver maintains an internal buffer of the most recent significant events.
To read the trace log, cat the ‘trace’ file. For example:
cat /sys/bus/scsi/drivers/pfo/trace
Library path failover events
When the library detects a path failover, it generates an appropriate event. Path failover events
do not always occur immediately following a path break. The device driver will wait until a
command is sent, and if the path is still failed, the device driver will perform the failover actions
and the library will report the event immediately after the failover. See the library user guide for
accessing and interpreting support tickets and log files.
• “ESL G3 events related to advanced path failover” (page 62)
• “MSL6480 events related to path failover” (page 63)
• “MSL library events related to path failover” (page 64)
Table 6 ESL G3 events related to advanced path failover
DescriptionEvent
A library control path failed and a failover operation to a redundant control
path drive succeeded.
Library Control Path Failover
A library control path failed and a failover operation to a redundant control
path did not succeed. The library control path is not operational.
Library Control Path Failover Failure
A drive data path connection failed and a failover operation to the
redundant drive port succeeded.
Drive Data Path Failover
A drive data path connection failed and a failover operation to the
redundant data port failed. The drive data path is not operational.
Drive Data Path Failover Failure
A drive communication failure occurred which prevents drive control and
library control path operations.
Drive Control/Communication Failure
62 Troubleshooting failover operation