HP P6000 HP P6300/P6500 Enterprise Virtual Array User Guide (593079-001, June - Page 132

6 Single path implementation This chapter provides guidance for connecting servers with a single path host bus adapter (HBA) to the Enterprise Virtual Array (EVA) storage system with no multipath software installed. A single path HBA is defined as: • A single HBA port to a switch with no multipathing software installed • A single HBA port to a switch with multipathing software installed HBA LUNs are not shared by any other HBA in the server or in the SAN. Failover action is different depending on which single path method is employed. The failure scenarios demonstrate behavior when recommended configurations are employed, as well as expected failover behavior if guidelines are not met. To implement single adapter servers into a multipath EVA environment, configurations should follow these recommendations. The purpose of single HBA configurations for non-mission critical storage access is to control costs. This chapter describes the configurations, limitations, and failover characteristics of single HBA servers under different operating systems. Several of the descriptions are based on a single HBA configuration resulting in a single path to the device, but OpenVMS has native multipath features by default. NOTE: Tru64 and NetWare are not supported with the P6300/P6500 EVA. With OpenVMS, a single HBA configuration will result in two paths to the device by having connections to both EVA controllers. Single HBA configurations are not single path configurations with these operating systems. In addition, cluster configurations for OpenVMS provide enhanced availability and security. To achieve availability within cluster configurations, configure each member with its own HBAs and connectivity to shared LUNs. For further information on cluster configurations and attributes, see the appropriate operating system guide and the HP SAN Design Reference Guide. NOTE: HP continually makes additions to its storage solution product line. For more information about the HP Fibre Channel product line, the latest drivers, and technical tips, and to view other documentation, see the HP website at: http://www.hp.com/country/us/eng/prodserv/storage.html Installation requirements • The host must be placed in a zone with any EVA worldwide IDs (WWIDs) that access storage devices presented by the hierarchical storage virtualization (HSV) controllers to the single path HBA host. The preferred method is to use HBA and HSV WWIDs in the zone configurations. • On HP-UX, Solaris, Microsoft Windows Server 2008, Microsoft Windows Server 2003 (32-bit), Windows 2000, Linux and IBM AIX operating systems, the zones consist of the single path HBA systems and one HSV controller port. • On OpenVMS, the zones consist of the single HBA systems and two HSV controller ports. This results in a configuration where there are two paths per device, or multiple paths. Recommended mitigations EVA is designed for the mission-critical enterprise environment. When used with multipath software, high data availability and fault tolerance are achieved. In single path HBA server configurations, neither multipath software nor redundant I/O paths are present. Server-based operating systems are not designed to inherently recover from unexpected failure events in the I/O path (for example, loss of connectivity between the server and the data storage). It is expected that most operating systems will experience undesirable behavior when configured in non-high-availability configurations. 132 Single path implementation