The non-mission-critical applications gain access to the EVA from a single path HBA server without
running a multi-path driver. When a single path HBA server uses the supported configurations, a fault
in the single path HBA server does not result in a fault in the other servers.
Benefits at a glance
The EVA is a high-performance array controller utilizing the benefits of virtualization. Virtualization
within the storage system is ideal for environments needing high performance, high data availability,
fault tolerance, efficient storage management, data replication, and cluster support. However,
enterprise-level data centers incorporate non-mission-critical applications as well as applications that
require high availability.
Single-path capability adds flexibility to budget allocation. There is a per-path savings as the additional
cost of HBAs and multi-path software is removed from non-mission−critical application requirements.
These servers can still gain access to the EVA by using single path HBAs without multi-path software.
This reduces the costs at the server and infrastructure level.
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 2003 (32-bit), Novell NetWare, Linux and IBM
AIX operating systems, the zones consist of the single path HBA systems and one HSV controller
port.
•
On OpenVMS and Tru64 UNIX operating systems, the zones consist of the single HBA systems
and two HSV controller ports. This will result 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 multi-path software,
high data availability and fault tolerance are achieved. In single path HBA server configurations,
neither multi-path 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.
Because of the risks of using servers with a single path HBA, HP recommends the following actions:
•
Use servers with a single path HBA that are not mission-critical or highly available.
•
Perform frequent backups of the single path server and its storage.
Supported configurations
All examples detail a small homogeneous Storage Area Network (SAN) for ease of explanation.
Mixing of dual and single path HBA systems in a heterogeneous SAN is supported. In addition to
this document, reference and adhere to the SAN Design Reference Guide for heterogeneous SANs,
located at:
http://h18006.www1.hp.com/products/storageworks/san/documentation.html
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