Host Failover

Hitachi Freedom Storage Lightning 9900 V Series Availability is Highest in the Industry

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 V Series supports each classification of middleware:

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 V Series systems support alternate pathing for IBM AIX®, HP® True64™ UNIX®, HP-UX®and through PVlink, Microsoft® Windows NT®/Windows® 2000, Sun™ Solaris™, and IBM DYNIX/ptx®.

Hitachi Dynamic Link Manager™ Software Provides Path Failover and Load Balancing

Hitachi Dynamic Link Manager™ software is a family of Hitachi-provided middleware software utilities that are ser ver-based, as shown in Figure 22. Dynamic Link Manager software enhances the availability of RAID systems by providing automatic-error recovery and path failover from server-to-RAID connection failures. Dynamic Link Manager software pr ovides 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 Dynamic Link Manager software is required for true nonstop operations. This product allows systems administrators to take advantage of the multiple paths on a Lightning 9900 V Series system by adding redundant connections between application servers and RAID systems. Dynamic Link Manager software therefore provides increased reliability and performance. Supported platforms include IBM AIX, Sun Solaris, Windows NT,

Windows 2000, and LINUX® (July 2003).

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 “takeover” includes the reassignment of networks and peripherals, as well as the restarting of applications. Host clustering can also be used to create fault-tolerant workloads and scale processor capabilities while sharing network and disk resources.

Lightning 9900 V Series systems supports all major open systems clustering schemes including: HP TruCluster™, HP MC/ServiceGuard™, HP MC/Lock Manager, IBM RS6000® and SP HACMP™, Windows NT/Windows 2000, Microsoft Cluster Server, NCR UNIX SVR4 Lifekeeper, IBM DYNIX/ptx ATAP, VERITAS Cluster Server™ for Sun Solaris and Red Hat® Advanced Server 2.1 and SuSE Enterprise Server 7.0 for LINUX®.

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

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

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