Redundant Electronics
The optional SL8500 or SL3000 Redundant Electronics (RE) feature provides failover protection in enterprise libraries. If the library controller experiences errors, it automatically switches operations to an alternate library controller, with minimal disruption to library and host operations. This allows your Oracle support representative to replace the faulty card while the library continues normal operations.
RE also provides minimal disruption of library operations during firmware upgrades.
Note:
The libraries offer redundancy in a variety of components, including robots and power systems. The term “Redundant Electronics" refers specifically to redundancy in the library and drive controller components.RE requires all of the following hardware components:
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Active library controller (HBC or HBCR) paired with the active drive controller (HBT)
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Standby HBC or HBCR paired with the standby HBT
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Other redundant components
For more information, refer to the StorageTek SL8500 or SL3000 User's Guide.
The following figure shows ACSLS with RE in a single library.
ACSLS Support for RE
ACSLS handles a mix of active and standby SL8500 Library Controller (LC) cards within a single library complex (an ACS of libraries connected by pass-thru).
As shown in the following figure, either of the HBCR cards in each SL8500 can be the active controller card.
Figure B-8 ACSLS with RE and Multi TCP/IP
Description of "Figure B-8 ACSLS with RE and Multi TCP/IP "
Each library in a string of connected SL8500s can now have its own pair of redundant Library Controllers. In a library complex, some libraries can have a pair of library controller cards, with RE enabled, while other libraries only have a single library controller. ACSLS should be able to communicate with all of the active LCs at the same time.
The following figures show ACSLS support for RE with Dual TCP/IP or with Dual and Multi TCP/IP.
Figure B-10 RE with Dual TCP/IP and Multi TCP/IP
Description of "Figure B-10 RE with Dual TCP/IP and Multi TCP/IP "
Query and Retry of Mounts and Dismounts
To support RE, ACSLS implemented the Query and Retry of mounts and dismounts during temporary library and drive outages. For more information, see Queue and Retry Mounts and Dismounts when Library is Temporarily Unavailable.