Host Cache Loss Detection and Recovery
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Solution Overview
Problem
Cache loss in storage devices due to device resets can lead to consistency errors in file systems, resulting in data loss and system instability, as the host is unaware of the cache loss and continues to operate, potentially causing further errors.
Innovation Solution
A host and storage device system where the host is configured to receive information about cache loss from the storage device after a reset, suspend data operations, and request cache information to perform consistency checks and error corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the storage device uses a volatile cache to increase write and read speeds, then the write and read speeds are improved, but the cache data may be lost due to power cycle, hardware reset, or software reset
Solution Approach 1:
The storage device performs a preliminary action by reporting cache loss information to the host before the host becomes unaware of the cache loss. When cache data is lost due to reset, the storage device proactively notifies the host, enabling the host to take corrective actions before consistency errors propagate through the file system.
Solution Approach 2:
A feedback mechanism is established where the storage device continuously monitors its cache status and provides feedback to the host about cache loss conditions. This feedback loop allows the host to adjust its operations based on the actual cache state, preventing data inconsistency issues.
2Productivity
If the host continues data operations after device reset without detecting cache loss, then the productivity is maintained, but consistency errors continuously increase
Solution Approach 1:
The host implements a feedback mechanism by receiving cache loss information from the storage device and adjusting its data operations accordingly. The host can suspend or modify I/O operations when cache loss is detected, preventing consistency errors from accumulating while maintaining productivity when the cache is healthy.
Solution Approach 2:
The host dynamically adjusts its data operations based on the cache status feedback received from the storage device. When cache loss is detected, the host can temporarily suspend operations and then resume them after verification, creating a dynamic operation mode that adapts to real-time cache conditions.
3Reliability
If the host performs file system consistency check (FSCK) after rebooting, then the consistency errors are detected and corrected, but the time for data input/output operations is lost
Solution Approach 1:
The consistency check process is triggered preliminarily upon detecting cache loss, rather than waiting for system failure. By performing the check immediately when cache loss is reported, the system prevents error accumulation that would otherwise require more extensive recovery procedures later, reducing overall time loss.
Solution Approach 2:
The system rushes through the consistency check process by performing it as a targeted operation immediately after cache loss detection, rather than allowing the system to continue operating with potential errors. This rapid verification prevents the need for more time-consuming recovery procedures if errors are allowed to accumulate.
Data Source
AI summary
A host for managing a storage device is provided. The host includes a storage host interface configured to communicate with the storage device comprising a cache and a non-volatile memory and at least one processor. The at least one processor may be configured to receive information indicating cache loss from the storage device after device reset of the storage device, suspend a data input/output operation for the storage device, transmit a buffer read command to the storage device, and receive cache information related to data remaining in the cache without being stored in the non-volatile memory before the device reset from the storage device in response to the buffer read command.