INCITS/T11 working group (see clause 6) in the FC-LS-2 specification. NPIV allows a single physical port
to connect to a Fibre Channel switch multiple times using multiple node and port names.
Advanced path failover
Advanced path failover uses capabilities in the LTO-6 tape drives and the libraries in which they are
installed, combined with software drivers running on a host system to provide path failover when multiple
paths are available to a tape drive or to a library controller. Advanced path failover is a licensed feature.
An example multi-path configuration is shown in
Figure 5: Example multi-path configuration
12.
Figure 5: Example multi-path configuration
In this example configuration, two different servers designated as “Server A” and “Server B” each have
two different host interface ports that are connected to two different SANs. Each SAN is connected to the
tape library. The connection between the library and the SAN in this example is a bundle of connections
that contains a connection to one port on each drive in the library. All of the drives in the library have two
ports with one port connected into SAN 1 and the second port connected into SAN 2. The library in this
example has two different drives which are both configured to provide a library control path. Each drive
that is configured to provide a library control path will connect to the SAN as two devices, a tape drive and
a library controller, at two different SCSI logical units.
The list of paths available at one of the servers is shown in the example path list. In this table, the SAN
that contains the path is listed in the first column and the following columns show what device is being
addressed (for example, the SCSI logical unit), the port on the drive that is being accessed, an example
SCSI address, and the worldwide identifier (such as a Fibre Channel worldwide node name) of the
addressed logical unit. The unique portion of the worldwide identifier is highlighted.
Table 1: Example path list
SAN
Addressed Logical
Unit
Port
Example SCSI
address
Example Logical Unit
Worldwide Identifier
1
Tape drive 1
Port A
ID 1 LUN 0
50:01:10:a0:00:00:00:
01
1
Library Controller
Port A
ID 1 LUN 1
50:01:10:a0:00:00:00:
02
Table Continued
12
Advanced path failover
