HP StoreEver High Availability Path Failover HP-UX Driver Release Notes (5697-3327, June 2014)

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Features
This section identifies features for first release of advanced path failover drivers.
• Drivers to be used with HP LTO-6 FC drives and the ESL G3 and MSL6480 tape libraries in which
they are installed.
• Drivers create entries in the system log when they are first started and whenever any exceptional
conditions occur.
Fixes
N/A
Issues and workarounds
This section identifies important issues and workarounds for Advanced Path Failover.
Current implementation is failure tolerant only and not intended to fix unstable
SAN environments.
Symptom: Device connectivity lost after several closely spaced path failures. If several closely spaced
path failures occur on all of the available paths the operating system might not detect a path change
and report that to the driver causing a loss of connectivity with the device.
Workaround: Locate and repair the SAN faults. The driver is not always able to recover if both the
active path and the standby path have faults.
HP-UX driver does not perform speed or performance comparisons of all available
paths to a device in order to select the best one as a primary.
Symptom: The device driver does not connect to the highest performance path after a system boot or
device rescan.
Workaround: The driver prefers the first path in the hardware scan performed by the operating system.
If a particular path is preferred, load the HBA for that path in the lower numbered hardware location.
A failure of the active control path drive and activation of the passive control
path drive near the same time that a reservation is being released may result in
the reservation not being released correctly.
Symptom: Tape library access commands fail with "Reservation Conflict" errors or "Medium Removal
Prevented" errors. In rare cases where access to all paths on the active control path drive is lost at the
same time that a reservation or prevent media removal setting is in the process of being changed or
if all paths are lost to an active control path drive in a multi-initiator environment and one host does
not recover from the path failure it is possible to have a reservation or prevention setting that is no
longer associated with a host. Note that this is not unique to the APF driver and is most likely to occur
in traditional multi-path configurations.
Workaround: Both the ESL G3 library font panel and the Windows diagnostic application provide a
method for clearing the stale settings. In the Windows diagnostic application it is found under
Actions→Clear Nexus Settings.
If the Windows diagnostic application or ESL G3 GUI is not available, most settings can be cleared
by using the library GUI to power-cycle the tape drive hosting the library controller. Persistent reservation
settings must be cleared using the application that established the settings.
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