SAS Target PHY Auto-Configuration via Common Address
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Solution Overview
Problem
Current SAS protocol lacks a defined mechanism for establishing wide port links in target phys, requiring manual intervention for configuration changes, such as when targets are moved or cabling changes occur, and lacks visibility into prior phy usage or selection, leading to suboptimal data transfer and power management.
Innovation Solution
A method and system that automatically manage target phys by transmitting a common phy address, storing it in non-volatile memory, and resetting phys to configure them into wide ports based on received host addresses, enabling dynamic reconfiguration and alignment with host opportunities without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual intervention is used to configure target phys into wide ports, then wide port configuration is achieved, but manual intervention is required for every configuration change
Solution Approach 1:
The target device automatically detects host wide port opportunities and configures its phys accordingly without requiring manual intervention. The controller monitors host communications and autonomously establishes wide port configurations when detected, eliminating the need for manual reconfiguration during system changes.
Solution Approach 2:
The target device pre-configures phys with common SAS addresses in non-volatile memory before connecting to the host. This preliminary preparation enables automatic wide port formation when the host presents matching common addresses, eliminating the need for manual configuration during system assembly or changes.
2Adaptability or versatility
If common SAS addresses are transmitted on multiple target phys, then wide port establishment is enabled, but the target cannot determine which phys the host may attempt to group
Solution Approach 1:
The target device transmits common SAS addresses on multiple phys and monitors host responses to determine which phys the host attempts to group. This feedback mechanism provides visibility into host phy selection preferences, enabling the target to adaptively configure wide ports based on actual host behavior rather than guessing.
Solution Approach 2:
The common SAS address acts as an intermediary signal that the target transmits on multiple phys to probe host preferences. By using this intermediary address, the target can indirectly determine host phy grouping intentions without direct communication about phy selection preferences.
3Reliability
If target phys are configured into wide ports, then link failure tolerance is improved, but the SAS protocol lacks a defined mechanism for wide port link establishment
Solution Approach 1:
The target device uses the existing SAS address transmission mechanism for multiple purposes: both for individual phy identification and for wide port establishment. By making the common SAS address transmission universal across all phys, the system achieves wide port configuration using existing protocol elements rather than requiring new complex mechanisms.
Solution Approach 2:
The target device autonomously establishes wide port links by detecting host opportunities and automatically configuring phys with common addresses. This self-service approach creates reliable wide port configurations without requiring complex external configuration mechanisms or manual intervention.
Data Source
AI summary
Embodiments of the present disclosure generally relate to managing phys of a data storage target device. In one embodiment, a method of managing phys of a data storage target device includes waiting to receive a host address on a target phy and transmitting a target phy address for the target phy after waiting to receive the host address on the target phy. In another embodiment, a method of managing phys of a data storage target device includes configuring a target port comprising a first target phy and reconfiguring the target port comprising a first target phy and a second target phy.