ACSLS HA is a hardware and software configuration that provides dual-redundancy, automatic recovery and automatic failover recovery to ensure uninterrupted tape library control service if component or subsystem failures occur. This document explains the configuration, setup and testing procedures required to provide High Availability to ACSLS software.

It is best to review the complete installation process before beginning the procedure. The process of installing a clustered application involves multiple steps requiring strict attention to detail. This procedure is normally undertaken by specialists in UNIX/LINUX system integration.

The configuration is a two-node system. It includes two complete subsystems (one active and one standby) with monitoring software capable of detecting serious system failures. It can switch control from the primary to the standby system for any non-recoverable subsystem failure. The configuration provides redundant power supplies, and redundant network and I/O interconnections that can recover subsystem communication failures instantly without the need for a general switch over.

The system leverages the monitor and failover features built in to ACSLS HA. The multipath features in the Linux operating system provide resilient library control operation with minimal downtime. Linux offers IP bonding to ensure uninterrupted network connectivity and multipaths to NFS disk I/O with RAID 1 to ensure uninterrupted access to system data. ACSLS HA monitors the health of system resources including the internal hardware and external I/O resources. It can also manage a system switch over if required.

The ACSLS HA agent monitors the ACSLS application, its database, its file system, and connectivity to StorageTek library resources, invoking the ACSLSHA failover service, if needed. In this redundant configuration, the ACSLS Library Control Server has a single logical host identity, which is always known within the framework and to the rest of the world. This identity is transferred automatically as needed between the nodes with minimal downtime during the transition.

Before embarking on the project, review the complete process of installing and configuring ACSLS HA as it is documented within this publication. If desired, Advanced Customer Services from Oracle can be arranged to advise, to assist, or to handle the entire installation.