HP StoreEver High Availability Path Failover Linux Driver Release Notes Version 1.0.5-1 (5697-3326, June 2014)

• 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.
• Diagnostic information is available via the /sys file system. See the HP StoreEver Tape Libraries
Failover User Guide for more information.
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.
Current implementation uses the first path to a device that was successfully found.
Symptom: The device driver does not connect to the preferred 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.
Linux 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.
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.
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: 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
4 Fixes