perspective, the next section of this white paper will describe how to incorporate Serviceguard into the solution to maximize overall availability.

Redundant Hardware Configurations within Blade Enclosures

For data center applications, the HP BladeSystem c7000 enclosure includes the following redundant components:

∙Up to 6 power supplies

∙Up to 10 Active Cool fan kits

∙Up to 8 interconnect modules

∙Redundant signal midplane paths

∙Redundant enclosure management using Active / Standby Onboard Administrators (OAs)

HP Integrity Server Blade redundancy features include:

∙Two dual-port Gigabit Ethernet embedded NICs (LOM)

∙3 Mezzanine I/O slots

∙Up to two internal SFF (Small Form Factor) SAS (Serial Attached SCSI) hot-plug hard drives (BL860c)

∙Up to four internal SFF SAS hot-plug disk drives (BL870c)

The following sections describe how to utilize many of these redundancy features in HP BladeSystem solution designs.

Redundant Enclosure Management

Redundant enclosure management is an optional feature of both the c3000 and c7000. Utilizing this feature requires installing a second HP BladeSystem Onboard Administrator (OA) module in the enclosure slot adjacent to the first OA to serve as a completely redundant controller in an active- standby mode. The redundancy logic of the OA module pair is based on a continuous heartbeat between the two modules over a dedicated serial connection in the signal midplane. If the period between heartbeats exceeds an internal timeout value set within the OA software, the standby module automatically takes control of the enclosure and becomes the active BladeSystem Onboard Administrator.

When two Onboard Administrator modules are installed in the enclosure, either module can be the active module with the other becoming the standby module. Configuration data is constantly replicated from the active Onboard Administrator module to the standby Onboard Administrator module, regardless of the bay in which the active module currently resides. If two Onboard Administrator modules of the same firmware revision are installed, the module on the left of the enclosure will be the active OA. If two Onboard Administrator modules installed into the same enclosure have different firmware versions, the automatic configuration synchronization feature is disabled.

When the active Onboard Administrator module fails, the standby Onboard Administrator module automatically becomes active. This occurs regardless of the position of the active Onboard Administrator module. This automatic failover occurs only when the currently active module comes completely offline and the standby module can no longer communicate with it. In all other cases, a system administrator must initiate the failover by logging into the standby module and promoting it to be the active Onboard Administrator. After the failed Onboard Administrator module is replaced (the modules are hot-pluggable), it automatically becomes the standby module and receives the

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