Windows Knowledge Base

[SAN HPUX]How to setup host connectivity for HPUX 11iV3 that connects to Clariion without Powerpath

There are basically four type of scenarios when setup host connectivity for HPUX11iV3 to EMC Clariion:
• PowerPath with ALUA - ALUA features are provided when the specified PowerPath release is used with the noted operating system.

• Native with ALUA - ALUA features are provided when using the noted operating system alone (PowerPath is not required.)
•  PowerPath with A/P - Standard Active/Passive failover (not ALUA) is provided by PowerPath with the noted operating system. (PowerPath issues trespass commands to enable alternate paths by changing SP LUN ownership.)
•  Native with A/P - Standard Active/Passive failover (not ALUA) is provided when using the noted operating system alone. (OS issues trespass commands to enable alternate paths.)
To enabled Native support for ALUA, 'failovermode 4' option need to be set on a CLARiiON array.
In "failovermode 4," both storage processors (SPs) will report that all non-owned units exist and are available for access (Inquiry Peripheral Qualifier code 0x00). If the SP is in the process of shutting down, an Inquiry Peripheral Qualifier code of 0x01 will be returned.
In addition, both SPs will accept and process media access commands to the logical unit. Internally, the logical unit is still owned by one of the SPs. The non-owning SP will internally forward the media access operation to the owning SP for processing. As a result, the array operates in what is termed an “Asymmetric Logical Unit Access" (ALUA) mode of operation. The owning SP will process commands more quickly and efficiently and is thus referred to as the “optimized path.” The non-owning SP will process commands less quickly and efficiently and is thus referred to as the “non-optimized path.”
The optimized path is driven by LUN ownership, which can be changed in one of four ways in Active/Active mode:
1. Explicit Trespass via Navisphere array management command.
2. Explicit Trespass via Mode Select (Trespass Page) SCSI command.
3. Explicit Trespass via Set Target Port Group SCSI command.
4. Implicit Trespass (within the array) if the I/O load on the non-optimized path exceeds the I/O load on the optimized path by a specified quantity of I/O.
The Auto-trespass setting of the logical unit is ignored in this mode of operation.

Below chart shows us the iniator type, ArrayCommpath and Failover mode.