Intel ZT 7102 CMM Redundancy, Synchronization and Failover, Hardware Redundancy Specification

Intel® NetStructureTMZT 7102 Chassis Management Module

CMM Redundancy, Synchronization and Failover

4.0CMM Redundancy, Synchronization and Failover

4.1Overview

The CMM supports redundant operation with automatic failover in chassis using redundant CMM slots. In systems where two CMMs are present, one acts as the active chassis manager and the other as standby. Both CMMs monitor each other, and either can trigger a failover if necessary.

Data is always synchronized from the active CMM to the standby CMM whenever any changes occur. Existing data on the standby CMM is overwritten. A full synchronization between the active and standby CMM occurs on initial power up or insertion of a new CMM. See Table 19, “CMM Synchronization” on page 40 for a list of data items that are synchronized between the active and standby CMM.

4.2Hardware Redundancy Specification

The following hardware interfaces exist for the support of redundancy and automatic failover:

•Cross-connected CMM present inputs (PRES_I#) and outputs (PRES_O#)

•Cross-connected CMM health inputs (HLY_I#) and outputs (HLY_O#)

•Cross-connected negotiation inputs (NEG_I) and outputs (NEG_O)

The active CMM monitors its PRES_I# and HLY_I# inputs to determine if it has a healthy standby CMM. The active CMM deasserts its HLY_O# output to trigger a failover to the standby CMM.

The cross-connected negotiation signals are used to assure that only one CMM is active at a time. At any time, the standby CMM can trigger a failover by driving its NEG_O output low.

4.3Synchronization

To ensure data on the standby CMM matches the data on the active CMM, the active CMM synchronizes its data with the standby CMM, overwriting any existing data on the standby CMM.

The CMMs will initially fully synchronize data from the active to the standby CMM approximately 30 seconds after the CMMs boot (which can take up to 2 minutes total for both CMM boot and synchronization). An insertion of a new CMM will also cause a full synchronization from the active to the newly inserted standby, which also takes 2 minutes. Partial synchronization will also occur any time files are modified or touched via the Linux* “touch” command. Date and time are synched every hour.

Note: During synchronization, the LEDs on the standby CMM may blink on and off as the healthevents that were logged in the SEL are synchronized.

The following items are synchronized between CMMs. During a full synchronization, all of these files and data are synchronized. A change to any of these files results in that file being synched. The active CMM overwrites these files on the standby CMM.

Technical Product Specification 39