User's Manual

The driver does not perform speed or performance comparisons of
all available paths to a device 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.
In multi-host environments, device discovery on a newly introduced
or rebooted host could be problematic if the library is not idle during
the discovery. (Windows and Linux)
Symptom: A host in a multi-initiator environment does not discover a path to the library controller
when it is booted or the devices are rescanned when another initiator is using the library. Some
applications create an exclusive connection to the tape library and prevent drivers from performing
proper discovery and binding. Note that this is not unique to the HP APF drivers and can occur in
environments not using the APF drivers as well.
Workaround: For Windows, reboot or rescan devices while the library is not being used. For Linux,
reboot or remove and re-insert the advanced failover drivers using modprobe while the library is
not being used.
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.
70 Known issues and workarounds