OpenSFF Management Module Specification

8. Configuration and Metadata Management

This section defines how configuration data and enclosure metadata are stored, validated, and backed up using the chassis-mounted SD Card. It also specifies the role of the Management Module in maintaining configuration continuity, as well as the use of software-defined parameters to optimize KVM control behavior.

8.1 Enclosure-Level Metadata Store

Enterprise Enclosures that support a Management Module (MM) SHALL provide an SD Card in SPI mode on the backplane. The SD Card contains:

• Chassis description and layout, including slot definitions and enclosure-level settings.
• Also serves as a backup target for MM configuration data

8.2 Validity by Module Type

• Full-featured MMs: MUST mount and use the SD Card as described.
• Pass-through MMs: SHALL ignore the SD Card and provide no configuration persistence. In this mode, the enclosure operates solely with its hardware defaults.

8.3 Boot Behavior (Full-featured MM only)

On boot, the MM SHALL attempt to validate the SD Card contents (e.g., by verifying SHA-256 checksums or equivalent integrity mechanisms).

• If the SD Card data is valid, the MM imports the chassis description into its runtime environment.
• If the SD Card is absent or the data is invalid, the MM continues operation using its internal configuration store.

8.4 Backup Behavior (Full-featured MM only)

The MM SHALL back up configuration data to the SD card only when major configuration changes occur.

8.5 Restore Behavior (Full-featured MM only)

The MM SHALL NOT automatically restore configuration from the SD Card.

• Restoration occurs only when explicitly requested through the management interface.
• By default, the MM prioritizes its internal storage to preserve continuity of operation.

8.6 Fallback Behavior (All MM types)

If the MM cannot access or parse the SD Card storage, of if a Pass-through MM is installed, the following functions remain fully operational at the hardware level:

• Physical KVM signal routing
• Internal management network pass-through

8.7 Software-defined Control Parameters (Full-featured MM only)

Certain aspects of KVM control behavior MAY be parameterized and stored on the SD Card, allowing them to be tuned in software for the specific enclosure hardware implementation. These parameters include, but are not limited to:

• Reset timing: Duration of reset assertions, timing between successive reset pulses, and pause intervals between reset sequences.
• Slot selection timing: Debounce periods, switching delays, and pause intervals needed to ensure reliable multiplexer settling when changing active nodes.
• Combined switch/reset sequences: Timing relationships between slot switching and node reset events.

By externalizing these values to the SD Card, Full-featured MMs can adjust their control behavior to match the characteristics of the enclosure’s multiplexer subsystem and related hardware components, while preserving interoperability across all OpenSFF-compatible systems.