HP StoreEver MSL2024, MSL4048, MSL8048, and MSL8096 Tape Libraries User and Service Guide (AK378-96059, December 2012)

Table Of Contents
With NPIV creating a virtual device on the switch port that the drive is connected, to both the tape
drive and the tape library are shown by the switch as independent devices even though they are
connected to the same physical port. As the library is presented to the host as an independent
device it can be managed independently from the tape drive.
In “NPIV virtual library connection” (page 25) the tape library contains two drives with both tape
drives connected to a Fibre Channel switch. The library is presented as a virtual device using the
same link one of the tape drives in the figure.
When the tape library detects that the control path should fail over to an alternate path it is able
to disconnect the library from the physical link and reconnect the library to the switch over the link
used by the other drive without disrupting that link. Both drives could be active reading or writing
and the library can be moved without disrupting the drive activity. The logical connection following
a control path failover event is shown in Figure 11 (page 26).
Figure 11 NPIV library connection following failover
2. Logical direct link to switch1. Physical link to switch sharing drive link
“NPIV library connection following failover” (page 26) shows that the logical link for the library
has moved and now shares the same physical link as the top drive. No changes to the physical
cabling were required and any other activity on the links was not disrupted.
Configuring failover
Configuring data path port failover
Enabling data path port failover
Data path failover may be used with the drive ports configured in loop mode or fabric mode. For
best results and compatibility with control path failover HP recommends that the drive ports be
configured in fabric mode and connected to a switch.
Data path failover is configured for each drive using the drive configuration options in the library
network management interface. “Enabling data path port failover” (page 27) shows the drive
configuration options in the library network management interface. In this example, data path port
failover is enabled for drive 1 but is not enabled for drive 2. Note that in this example control path
26 Features and overview