Users Guide

13
Managing Fabrics
The chassis supports a fabric type, which is Fabric A. Fabric A is used by the single I/O Module, and is
always connected to the on-board Ethernet adapters of the servers.
The chassis has only one I/O module (IOM), where the IOM is a pass-through or switch module. The I/O
Module is classified as group A.
Chassis IOM uses a discrete data path called Fabric, and it is named A. The Fabric A supports only
Ethernet. Each server IO adapter (Mezzanine Card or LOM) can have either two or four ports depending
on the capability. The mezzanine card slots are occupied by PCIe extension cards that are connected to
PCIe cards (and not to IO modules). When you deploy the Ethernet, iSCSI, or FibreChannel networks,
span their redundant links across banks one and two for maximum availability. The discrete IOM is
identified with a fabric identifier.
NOTE: In the CMC CLI, the IOM is referred to by the convention, switch.
Invalid Configurations
There are three types of invalid configurations:
• Invalid MC or LOM configuration, where a newly installed fabric type of the server is different from the
existing IOM fabric, that is, a single server’s LOM or MC is not supported by its corresponding IOM. In
this case, all the other servers in the chassis are running, but the server with the mismatched MC card
cannot be turned on. The power button on the server flashes Amber to alert a fabric mismatch.
• Invalid IOM-MC configuration, where a newly installed fabric type of the I/O Module, and the resident
MC’s fabric types do not match or are incompatible. The mismatched IOM is held in the power-off
state. CMC adds an entry to CMC and hardware logs noting the invalid configuration and specifying
the IOM name. CMC causes the error LED on the offending IOM to blink. If CMC is configured to send
alerts, it sends email and/or SNMP alerts for this event.
• Invalid IOM-IOM configuration, where a newly installed IOM has a different or incompatible fabric
type from an IOM already installed in its group. CMC holds the newly installed IOM in powered-off
state, causes the IOM’s error LED to blink, and logs entries in CMC and hardware logs about the
mismatch.
Fresh Power-up Scenario
When the chassis is plugged in and turned on, the I/O module has priority over the servers. The IOM is
allowed to turn on before the others. At this time, verification of their fabric types is not performed.
After the IOMs turn on, the servers turn on, and then CMC verifies the servers for fabric consistency.
A pass-through module and switch are allowed in the same group if their fabric is identical. Switches and
pass-through modules can exist in the same group even if they are manufactured by different vendors.
Monitoring IOM Health
For information about monitoring IOM health, see Viewing Information and Health Status of the IOM.
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