IBM Europe, Middle East, and Africa Hardware
Announcement ZG14-0114
IBM is a registered trademark of International Business Machines Corporation
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cartridges, for applications which do not support mixing the drives in the same
logical library.
Advanced Library Management System (ALMS)
ALMS virtualizes the locations of cartridges in the TS4500 tape library and is
an extension of patented IBM Multi-Path Architecture. With ALMS, the TS4500
tape library is able to virtualize the locations of cartridges (called SCSI element
addresses) while maintaining native SAN attachment for the tape drives. ALMS
enables logical libraries to consist of unique drives and ranges of volume serial
(VOLSER) numbers instead of fixed locations.
The TS4500 tape library comes with ALMS so that you can immediately start
assigning tape drives to any logical library by using the TS4500 management GUI.
Logical libraries can also be added, deleted, or easily changed without disruption.
Storage capacity can be changed without impact to host applications.
ALMS offers dynamic management of cartridges, cartridge storage slots, tape drives,
and logical libraries. It enables the TS4500 tape library to achieve unprecedented
levels of integration for functionality through dynamic partitioning, storage slot
pooling, and flexible drive assignment. ALMS eliminates downtime when you add
Capacity On Demand (CoD) or High Density Capacity on Demand (HD CoD) storage,
add or remove logical libraries, or change logical library storage allocation. ALMS
also reduces downtime when you add expansion frames, add or remove tape drives,
or change logical drive allocation.
ALMS provides the following capabilities:
• Dynamic partitioning through storage slot pooling and flexible drive assignment
• The transparent ability to add or remove storage capacity to any host application
• The ability to configure drives or to configure storage capacity without taking the
library offline
• Continuously enabled virtual I/O slots to automatically manage the movement of
cartridges between I/O slots and storage slots
Control path failover, data path failover, and load balancing
The path failover feature of the TS4500 tape library ensures the use of a redundant
path in the event that communication over the primary path fails.
Command failures and time-outs are costly. You want your library to run smoothly
and efficiently. To ensure continued processing, libraries that are equipped with Fibre
Channel LTO and 3592 tape drives offer path failover and load balancing capabilities
that enable the IBM device driver to resend a command to an alternate path. The
alternate path can include another host bus adapter (HBA), Storage Area Network
(SAN), or library control path drive. The device driver initiates error recovery and
continues the operation on the alternate path without interrupting the application.
Path failover and load balancing are built-in features that are enabled by using a
purchased license key.
There are two types of path failover capabilities exist: control path failover (CPF)
and data path failover (DPF). Control refers to the command set that controls the
library (the SCSI Medium Changer command set on LUN 1 of the tape drives). Data
refers to the command set that carries the customer data to and from the tape
drives (the SCSI-3 Stream Commands (SSC) device on LUN 0 of the tape drives).
Path failover refers to when there is redundancy in the path from the application to
the intended target (the library accessor or the drive mechanism, respectively), the
device driver transparently fails over to another path in response to a break in the
active path.
Both types of failover include host-side failover when configured with multiple HBA
ports into a switch, but CPF includes target-side failover through the control paths
that are enabled on more than one tape drive. DPF includes target-side failover for
the dual-ported tape drives that are supported by the TS4500 tape library.
