About Standby CMCThe standby CMC is identical to and is maintained as a mirror of the active CMC. The active and standby CMCs mustboth be installed with the same firmware revision. If the firmware revisions differ, the system reports as redundancydegraded.The standby CMC assumes the same settings and properties of the active CMC. You must maintain the same firmwareversion on both CMCs, but you do not need to duplicate configuration settings on the standby CMC.NOTE: For information about installing a standby CMC, see theHardware Owner’s Manual. For instructions oninstalling CMC firmware on your standby CMC, follow the instructions in Updating Firmware.CMC Failsafe ModeIn the failsafe mode, similar to the failover protection offered by the redundant CMC, the M1000e enclosure enables thefail-safe mode to protect the blades and I/O modules from failures. The fail-safe mode is enabled when no CMC is incontrol of the chassis. During the CMC failover period or during a single CMC management loss:• You cannot turn on newly installed blades.• You cannot access existing blades remotely.• Chassis cooling fans run at 100% for thermal protection of the components.• Blade performance reduces to limit power consumption until management of the CMC is restored.The following are some of the conditions that can result in CMC management loss:• CMC removal — Chassis management resumes after replacing CMC, or after failover to standby CMC.• CMC network cable removal or network connection loss — Chassis management resumes after the chassis failsover to the standby CMC. Network failover is only enabled in redundant CMC mode.• CMC reset — Chassis management resumes after CMC reboots or chassis fails over to the standby CMC.• CMC failover command issued — Chassis management resumes after the chassis fails over to the standby CMC.• CMC firmware update — Chassis management resumes after CMC reboots or chassis fails over to the standbyCMC. It is recommended that you update the standby CMC first so that there is only one failover event.• CMC error detection and correction — Chassis management resumes after CMC resets or chassis fails over tothe standby CMC.NOTE: You can configure the enclosure either with a single CMC or with redundant CMCs. In redundantCMC configurations, if the primary CMC loses communication with the enclosure or the managementnetwork, the standby CMC takes over chassis management.Active CMC Election ProcessThere is no difference between the two CMC slots; that is, slot does not dictate precedence. Instead, CMC that isinstalled or booted first assumes the role of the active CMC. If AC power is applied with two CMCs installed, CMCinstalled in CMC chassis slot 1 (the left) normally assumes the active role. The active CMC is indicated by the blue LED.If two CMCs are inserted into a chassis that is already powered on, automatic active/standby negotiation can take up totwo minutes. Normal chassis operation resumes when the negotiation is complete.35
