Procedure
1.
To minimize the level of debug messages:
echo 0x0000 > /sys/bus/scsi/drivers/pfo/debug_flag
2.
To maximize the level of debug messages:
echo 0xffff > /sys/bus/scsi/drivers/pfo/debug_flag
Increased debug logging will affect performance.
3.
To set the default level of debug messages:
echo minimum > /sys/bus/scsi/drivers/pfo/debug_flag
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 then the library will report the
event immediately after the failover. See the library user guide for accessing and interpreting support
tickets and log files.
• See ESL G3 events related to advanced path failover table below
• See MSL6480 events related to path failover table below
• See MSL library events related to path failover table below
Table 6: ESL G3 events related to advanced path failover
Event
Description
Library Control Path Failover
A library control path failed and a failover operation to a
redundant control path drive succeeded.
Library Control Path Failover Failure A library control path failed and a failover operation to a
redundant control path did not succeed. The library control path is
not operational.
Drive Data Path Failover
A drive data path connection failed and a failover operation to the
redundant drive port succeeded.
Drive Data Path Failover Failure
A drive data path connection failed and a failover operation to the
redundant data port failed. The drive data path is not operational.
Drive Control/Communication
Failure
A drive communication failure occurred which prevents drive
control and library control path operations.
Reading the trace log
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