Chapter 8. IBM BladeCenter HX5 377installed option rather than having to look at the entire server to try to find a good startingpoint during problem determination.8.2 Planning to scale: PrerequisitesAs described in 5.8, “Scalability” on page 188, the HX5 blade architecture allows for threescalable configurations: Single-node server: A single HX5 server with two processor sockets Two-node server: Two HX5 servers connected to form a single image 4-socket server HX5+MAX5: A single HX5 server with two processor sockets, plus a MAX5 memoryexpansion blade that is attached to the server.When making the decision to scale with either a MAX5 or by adding a second blade, you mustmeet several key prerequisites before proceeding: Processors supported and requirements to scale Minimum memory requirement Required firmware of each blade and the AMMWe describe these prerequisites in the following sections.8.2.1 Processors supported and requirements to scaleTwo-node configurations can include four processors (two in each node) or two processors(one in each node). When implementing a 4-processor configuration, all processors must beidentical and can be any of the supported Intel Xeon 7500 processors that are listed in 5.9,“Processor options” on page 192. Intel Xeon 6500 series processors are not supported in4-processor configurations. When implementing a 2-node configuration with one processor ineach node, both processors must be identical; however, any of the Xeon 7500 or Xeon 6500series processors that are listed in 5.9, “Processor options” on page 192 are supported.If you install two Xeon 6500 processors in either a 1-node or 2-node configuration and thenlater decide to upgrade to four processors in a 2-node configuration, you must replace theXeon 6500 processors with Xeon 7500 processors, because Xeon 6500 processors are notdesigned to scale to 4-way.Figure 8-5 shows an example of an error that you will see in the error log of the AMM if theprocessors do not match when trying to scale.Figure 8-5 Processor mismatch error when trying to scale a 2-nodeThe HX5+MAX5 configurations support all of the processors that are listed in 5.9, “Processoroptions” on page 192.8.2.2 Minimum memory requirementFor a 2-node configuration, the minimum required amount of memory is four DIMMs, two oneach blade in slots 1 and 4. However, we do not recommend this amount of memory forperformance reasons.
