Hitachi 9960, 9900 Series manual Host Failover

Hitachi High Availability Software Improves Application Service Levels

There are four basic types of high-availability middleware that can reduce downtime in the event of a data path or host failure. The Lightning 9900™ supports each classification of middleware:

1.Alternate Pathing middleware switches the I/O load in the event of path failure

This type of middleware automatically switches the I/O load on a failed primary path to an alternate path on the same host system. The Lightning 9900 support alternate pathing for AIX® 4.2 and above, Compaq True64™ UNIX®, HP® 10.01 and through PVlink, Windows NT/2000® and Sun Solaris™ 2.5 and Sequent DYNIX/ptx®. In addition, VERITAS® Dynamic Path Management™ (DPM) is supported.

2 . Hitachi Dynamic Link Manager™ provides path failover and load balancing

Hitachi Dynamic Link Manager™ is a family of Hitachi-provided middleware software utilities that are server-based as shown in Figure 22. Hitachi Dynamic Link Manager™ enhances the availability of RAID systems by providing automatic error recovery and path failover from server-to-RAID connection failures. Hitachi Dynamic Link Manager™ provides load balancing in addition to path failover by re-directing I/O activity to the least busy path using complex algorithms.

Just because a system is RAID-protected doesn’t mean it is protected against connection bus failures, which is why Hitachi Data Link Manager™ is required for true non-stop operations. This product allows systems administrators to take advantage of the multiple paths on a Lightning 9900™ by adding redundant connections between application servers and RAID systems. Hitachi Dynamic Link Manager™ therefore provides increased reliability and performance. Supported platforms include AIX®, Sun Solaris™, Windows NT®, and Windows 2000®.

3.Host Failover

Host failover software supports a cluster of host processors in which one of the hosts automatically takes over the workload of any failed host in the cluster. This “take-over” includes the reassignment of networks and peripherals, as well as the restarting of applications. Host clustering can also be used to create fault-tolerant work loads and scale processor capability while sharing network and disk resources.

The Lightning 9900™ supports all major open systems clustering schemes including: Compaq TruCluster®, HP® MC Service Guard, HP® MC Lock Manager, IBM® RS6000 and SP HACMP, Windows NT/2000®, Microsoft® Cluster Server, NCR® UNIX® SVR4 Lifekeeper, IBM DYNIX/ptx ATAP®, and VERITAS ClusterServer™ for Sun Solaris™.

Alternate pathing automatically switches the I/O load on a failed primary path.

Hitachi Dynamic Link Manager™ provides load balancing in addition to path failover.

One of the hosts automatically takes over the workload of any failed host in the cluster.

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