HP-UX iSCSI Software Initiator Support Guide (Edition 7)

B Transport Statistics
B.1 Transport Statistics
Transport statistics are explained in Table 4: “Transport Statistics” (page 42).
The Class column (CL) provides message classification. Messages can be informational (I), target
errors (T), transient driver errors (D), or connectivity problems (C).
Informational Messages are counters for driver events. They are not an indication of an error, but
should an error occur, they may provide some profiling information.
Target Errors are detected at the initiator and should be reported to HP and/or the target vendor.
Not all target errors are reported on the host side, and it is the responsibility of the system
administrator to monitor any device specific logs for target issues.
Transient Driver Errors typically occur when some resource, for example, memory, is in short
supply, or something is not configured correctly. The error is considered transient, because a retry
of the operation, or a correct re-configuration, is typically successful. I/Os that experience transient
errors are retried, so no data is lost. Control operations such as an application open, or a task
management command, may not be retried (the determination to retry is left to the application or
to the administrator). If the system resource load is increased, a small value for a transient driver
error statistic may be an indication of problems. Larger values for the transient driver error statistic
will start to impact performance.
Connectivity Problems are typically network or target availability problems. Connectivity problems
are transient in the sense that a network infrastructure engineer can resolve the problem and I/O
traffic will resume as before.
Table 4 Transport Statistics
Description of FieldCLiscsiutil Statistic
Transport Global Statistics
The total number of times the iSCSI subtree of nodes has been
scanned.
INumber of ioscan’s issued
The number of discovery sessions that were opened to discover
new targets. A discovery session is opened for each iSCSI
INumber of Discovery sessions opened
target port during an ioscan. A single ioscanwould
therefore result in a separate discovery session for each target
port (portal group).
The number of attempted discovery sessions that failed. The
failure is due to an inability to open a connection. Some of
the reasons why a connection open might fail are:
D/CNumber of Discovery session open failures
• Initiator/host name not configured.
• Hostname could not be resolved (confirm that iscsi_resolvd
daemon is running).
• Target is unreachable (network or target problems).
• Resource allocation failures (memory, ISID, target ).
The number of normal sessions that were opened. Normal
sessions are opened to perform I/O. In general, normal
sessions are any session other than discovery sessions.
INumber of Normal sessions opened
The number of attempted normal/operational sessions that
failed. The failure is due to an inability to open a connection.
Some of the reasons why a connection open might fail are:
D/CNumber of Normal session open failures
• Hostname could not be resolved (confirm that iscsi_resolvd
daemon is running).
• Target is unreachable (network or target problems).
• Resource allocation failures (memory, ISID, target).
42 Transport Statistics