Configuration; Configuration Planning; Hafo Configuration Restrictions - HP e3000 MPE/iX Manual

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Configuration

Once HAFO software is installed, the core components are active. This means
HAFO is monitoring the I/Os for any HAFO (like) reply messages, as
documented in Chapter 2, "Product Description." However, for failover
protection, the Ldevs must be configured for HAFO and the configuration must
be activated.
Configuring an Ldev creates an entry in the HAFO configuration file,
HAFOCONF. The HAFOCONF file resides in the configuration group on Ldev1.
It contains one record for each Ldev configured for FAILOVER. If you are
updating from MPE/iX 6.5 with an existing, active HAFO configuration you
will have some additional steps to recreate your HAFOCONF file. See the
"Chapter 4 Configuration –"Special Considerations" section for details.

Configuration Planning

Detailed planning of the hardware configuration of the array itself and the actual
HAFO configuration (in SYSGEN) is required. Before taking any action on the
array or in SYSGEN, the user should have a complete map and plan for the
setup. The path layout and primary and alternate paths for all the Ldevs to be
covered by HAFO must be determined in advance. Both user and system
volumes may be configured for high availability failover. All Ldevs covered by
HAFO must be on supported high availability storage arrays (see chapter 3).
Before beginning HAFO configuration in SYSGEN, the array must already be
cabled and the hardware configured to work with the HAFO utilities, as
described earlier in this document.
It is possible that a poorly performing Disk Array could actually trigger false
HAFO events. If a system is experiencing any problems with Disk Array
response times or I/O throughput it is not a good candidate for HAFO. If you are
planning to add HAFO to an existing system then it is recommended that
performance data for the system be analyzed to ensure that there are no disk I/O
bottlenecks. At a minimum, it is a good idea to check system logs for I/O
Timeout errors.

HAFO Configuration Restrictions

1. HAFO works with pairs of controllers. That is, all Ldevs on a given
2. All Ldevs on a given Host Bus Adaptor path must be configured in a
primary path/controller, for example (path A) must be configured to failover
to the same alternate path (path B). By the same token, any Ldevs that
happen to have path B as their primary path, must be configured to have path
A as their alternate path.
similar manner.. That is, if any Ldev on the HBA path is configured for
failover, then all Ldevs on the path must be configured for failover to the
same alternate path.
Configuration
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