Flash Storage Solutions for Embedded Designs
High Reliability Flash SSDs, Cards and Modules for Industrial Applications
Posted by David Chen on Wednesday, 01 Mar 2023
Embedded computing systems are designed to be highly efficient and effective, allowing them to perform specific tasks such as rapidly writing data to storage media quickly and accurately. While hard disk drives (HDDs) remain a viable storage option, especially where large amounts of data need to be written, their mechanical components can be vulnerable to damage from environmental influences such as shock and vibration in industrial settings, resulting in higher error rates. Consequently, Solid State Drives (SSDs) are most often preferred in rugged industrial storage settings because they lack moving parts and can withstand environmental impact much better than HDDs.
However, the biggest drawback of using Flash Memory Based Storage Solutions or SSDs is that flash memory storage has a finite lifespan based on the number of program and erase cycles written to the media. And write amplification can significantly shorten this lifespan.
Write amplification is a phenomenon the occurs when flash memory and solid state drives (SSDs) store more data than was originally intended, leading to an more write/erase cycles that compromise the device's lifespan and performance. To measure write amplification, it is necessary to compare the amount of data written to the flash memory with the amount intended to be stored by the application's host system. When compared to HDDs, SSDs are more susceptible to write amplification, as they require data to be erased before new data can be written, whereas HDDs permit new data to be written over old data. To understand why and how write amplification occurs in SSDs, it is essential to understand how they store data.
SSDs store data in cells that are organized into pages and then into blocks. While writing data onto an SSD, it can be stored in different pages and blocks, which is efficient for storing information but less efficient when erasing data. This scattered data can make it difficult for the SSD to locate and delete it. Furthermore, SSDs can only erase blocks of data at a time, which differs from how data is stored in specific cells and pages. To address these issues, SSD manufacturers have developed a process called garbage collection. This process saves data and rewrites it to another block that has already been erased, avoiding an information overload. The block containing the original data is then erased after all of the data has been transferred. However, this process causes data to exist twice, which can affect memory space and the SSD's limited program and erase cycles. Although it is impossible to eliminate write amplification entirely, garbage collection can reduce its adverse effects. SSDs require sufficient space for data to transfer safely onto new blocks during the erasure process. By understanding how SSDs store data and utilizing garbage collection, it is possible to minimize the impact of write amplification on SSD performance and lifespan.
TRIM commands are another way to reduce write amplification on SSDs. These commands notify the drive where data is no longer in use, erasing blocks internally for more efficient functionality. By preventing invalid LBA addresses from being included during garbage collection, TRIM reduces the likelihood of write amplification. It is essential to overwrite data rather than just marking it for deletion to prevent old data from being left behind during garbage collection. The TRIM command instructs the drive to erase the LBA as soon as a file is deleted, freeing up space for new data and avoiding write amplification. Although TRIM is highly efficient, it may not take effect until several garbage collection cycles have been completed, and significant space has been freed up in specific blocks on the drive. Additionally, not all SSDs support TRIM, and firmware updates may be necessary to realize similar benefits. Therefore, it is crucial to keep SSD firmware up-to-date and implement TRIM wherever possible to minimize the risk of write amplification on these devices.
Fortasa Memory Systems, Inc. offers highly customized industrial storage solutions that cater to clients' specific needs and offer exceptional customer service. We conduct extensive in-house testing to ensure data reliability and prolonged device lifespans, and can effectively prevent or address write amplification issues. When choosing a flash drive, it is important to consider write amplification in addition to factors such as speed, capacity, and flash grade. Fortasa Memory Systems, Inc. offers industrial-grade embedded applications that are both innovative and high-quality, with customized options available to meet specific design needs. For more information on preventing write amplification effectively, contact Fortasa Memory Systems, Inc. today.