SSDs (Solid State Drives) are essential hardware components for high-performance storage solutions. Solid state technology is non-volatile but may face data integrity risks in cases of sudden power loss or when supplied by an unstable power source. To mitigate these risks, Solid State Storage Technology Corporation (SSSTC) has developed its own power loss protection (PLP) technology with TruePLP, a crucial innovation for safeguarding data in such scenarios to eliminate unwanted and unexpected data loss.
During operation, the data, instructions, and mapping tables of the SSD are temporarily stored in a DRAM cache for improved latency and reduced wear. However, DRAM is volatile by nature and requires a continuous external power source to operate normally. In a standard system shutdown procedure, the host is able to send commands to the SSD’s controller to notify it of the impending power loss. This allows the SSD sufficient time to complete current operations and to commit data to the non-volatile NAND flash. However, in the event of an abrupt or unexpected power loss, the cached data is unable to be transferred to the flash memory which results in data errors and incomplete updates. This can lead to data loss, data corruption, or even device failure.
What Is TruePLP?
(1) A vital mechanism to safeguard SSD data during a sudden power loss event
The essence of TruePLP lies in utilizing high-reliability capacitors to provide hold-up power, ensuring the SSD has sufficient time during unexpected outages to halt ongoing tasks in order to prioritize data integrity. When a sudden power loss event occurs, TruePLP provides the capability for the SSD to write “in-flight data” as well as any “cached metadata” from volatile DRAM. Critical metadata includes the mapping table, event log, and system table, which are written in the NAND flash prior to full shutdown. The TruePLP mechanism is thereby able to prevent data loss while preserving data integrity so that normal system operation is maintained following a subsequent power-on.
(2) Intelligent power management for uninterrupted data transmission
TruePLP features intelligent power management, integrating a voltage detector within the power management integrated circuit (PMIC) for a more efficient and stable supply of power. This guarantees timely TruePLP activation during power outages or voltage instability in order to protect your data. It works through constant monitoring of the host power supply’s voltage level via the integrated voltage detector. When the host power supply voltage drops to a critical threshold level, this system automatically switches to the capacitors for a backup power source. This switch ensures that ample power is supplied to the SSD so that it can execute necessary write commands, fully clear any cached data, and flush critical data from the volatile DRAM cache to the non-volatile NAND flash.
(1) SSDs designed with TruePLP technology are equipped with ample backup capacitors. These capacitors provide sufficient power to safeguard against data loss even in the most adverse power failure scenarios.
(2) With TruePLP, the health status of the capacitors is recorded in the SSD’s S.M.A.R.T. values. In case of any detected abnormalities, users can promptly assess the situation through these reported values. The S.M.A.R.T. values may also be monitored to detect any significant changes during operation for immediate feedback.
(1) Under normal power supply conditions, the capacitors act as energy storage, charging via the host's power supply.
(2) If the host's power supply is unexpectedly cut off, these charged capacitors serve as a backup power source for the SSD.
(3) When the host's power supply voltage drops to a critical threshold, intelligent power management automatically switches the power source to the backup capacitors.
(4) The SSD controller may then issue the necessary shutdown commands, clearing the cache buffer and writing data to the NAND flash.
(5) After completion, the SSD is gracefully shut down.
(6) When the host's power supply is restored and the system is restarted, the mapping table in NAND flash is detected and utilized to resume normal operation.
Other PLP Technologies
There are PLP technologies that do not rely on capacitors but instead implement SSD power loss protection through firmware design. In such PLP designs, the firmware monitors the power status and may include a voltage detector. When an abrupt power loss is detected, the firmware initiates corresponding procedures to safeguard the integrity of the data. This mechanism attempts a reconstruction of the mapping table upon the next power-on following an outage, minimizing the risk of data loss. While this process can immediately halt the reception of write commands from the host upon detecting unstable power supply, it cannot write in-flight or cached data to the NAND flash, only protecting data-at-rest.
While this approach reduces the risk of SSD damage and can lower hardware costs, the absence of capacitors renders it incapable of completing ongoing write operations during any unexpected power loss event. This becomes a significant issue when writing large volumes of data. Therefore, its effectiveness in ensuring data integrity and reliability in the event of power loss is relatively limited and cannot be relied upon for mission-critical storage.
The Solid State Storage Technology Corporation, with many years of experience in the SSD industry, boasts a professional in-house R&D team with internally-developed firmware to offer flexible, tailored solutions for any customer demand. Enterprise-level storage solutions engaged in I/O-intensive workloads and applications need a reliable power supply to not only prevent data loss but also to mitigate associated maintenance costs. The addition of TruePLP technology, which combines firmware with a proven hardware solution, is an optimal and cost-effective choice that will reduce downtime for your storage infrastructure.
Solid State Storage Technology Corporation's enterprise-grade SSDs, such as the ER2 series, ER3 series, and PJ1 series, all feature TruePLP technology.