IBM System Storage TS3310 Setup And Operator Manual page 57

Using Persistent Binding to Ensure SCSI ID Assignment
When a server is booted, devices are discovered and assigned SCSI target and
LUN IDs. It is possible for these SCSI assignments to change between boots. Some
operating systems do not guarantee that devices will always be allocated the same
SCSI target ID after rebooting. Also, some software depends on this association, so
you do not want it to change. The issue of SCSI ID assignment is addressed by
persistent binding.
Persistent binding is an HBA function that allows a subset of discovered targets to
be bound between a server and device. Implemented by a WWNN or WWPN,
persistent binding causes a tape drive's WWN to be bound to a specific SCSI target
ID. After a configuration has been set, it survives reboots and any hardware
configuration changes because the information is preserved. If a drive needs to be
replaced, the new drive assumes the WWNN of the old drive because the WWNN
for the drive is location-dependent within the library. Because the WWNN does
not change, persistent binding does not need to be changed which would cause an
outage.
Fibre Channel Connectors and Adapters
The library is supported by a wide variety of servers (hosts), operating systems,
and adapters. These attachments can change throughout the product's life cycle. To
determine the latest supported attachments, visit the web at http://www.ibm.com/
storage/lto.
Sharing on a Storage Area Network
With Storage Area Network (SAN) components, the possibilities for connecting
multiple systems and multiple drives have increased. Not all software and systems
are designed to share drives. Before you install a drive that would allow two
systems to share it, check that the systems and their software support sharing. If
your software does not support sharing, note that Fibre Channel switches have a
zoning capability to form a SAN partition. For systems that do not cooperate, use
zoning to prevent the systems from sharing the same drive. You can remove zoned
partitions as you upgrade software and system levels.
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Chapter 2. Installation Planning