Using Multiple Control Paths For Iseries And As/400; Using Multiple Control Paths For Control Path Failover; Using Multiple Data Paths For Data Path Failover - IBM System Storage TS3310 Setup And Operator Manual

To add or remove additional control paths, refer to "Adding a Control Path Drive
to a Logical Library" on page 7-14. For a particular logical library, you can enable
as many control paths as there are drives in that logical library.

Using Multiple Control Paths for iSeries and AS/400

Attachment
The use of control paths for the iSeries and AS/400 servers is unique. In general,
every iSeries adapter must recognize the control path that is associated with the
drives to which it is connected. For the iSeries and AS/400 servers, one to six
drives are supported by LVD and Fibre Channel adapters and the OS/400 5.1,
OS/400 5.2, or OS/400 5.3 operating system.

Using Multiple Control Paths for Control Path Failover

Command failures and timeouts are costly. You want your library to run smoothly
and efficiently. To ensure continued processing, the library offers an optional
control path failover feature that enables the host device driver to resend the
command to an alternate control path for the same logical library. With control
path failover installed, the alternate control path can include another HBA, SAN,
or library control path drive. The device driver initiates error recovery and
continues the operation on the alternate control path without interrupting the
application. AIX, Linux, Solaris, HP-UX, and Windows hosts are currently
supported for this feature.
The Control Path Failover feature can be installed by the customer. For ordering
information, see Chapter 12, "Parts List," on page 12-1.
Note: The Control Path Failover feature is activated by a license key.
For more information about using the control path failover feature, see the IBM
Ultrium Device Drivers Installation and User's Guide.
Note: LTO-3 SCSI and Fibre Channel drives are not allowed in the same logical

Using Multiple Data Paths for Data Path Failover

Data Path Failover and Load Balancing exclusively supports native Fibre Channel
Ultrium 3 Tape Drives in the library using the IBM device driver for AIX and
Linux. Data Path Failover is designed to provide a failover mechanism in the IBM
device driver, which enable multiple redundant paths to be configured in a SAN
environment. In the event of a path or component failure, the failover mechanism
is designed to automatically provide error recovery to retry the current operation
using an alternate, pre-configured path without aborting the current job in
progress. This allows flexibility in SAN configuration, availability, and
management.
When accessing a tape drive device that has been configured with alternate paths
across multiple host ports, the IBM device driver automatically selects a path
through the host bus adapter (HBA) that has the fewest open tape devices and
assigns that path to the application. This autonomic self-optimizing capability is
called Load Balancing. The dynamic load balancing support is designed to
optimize resources for devices that have physical connections to multiple HBAs in
the same machine. The device driver is designed to dynamically track the usage on
each HBA as applications open and close devices, and balance the number of
applications using each HBA in the machine. This may help optimize HBA
library.
Chapter 2. Installation Planning
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