What is SSD Trim?
TRIM is a command for the ATA interface. As you use your drive, changing and deleting information, the SSD needs to make sure that invalid information is deleted and that space is available for new information to be written. Trim tells your SSD which pieces of data can be erased.
The command is different for other interfaces, and goes by different names in different operating systems, but the action is usually referred to as "Trim". No matter what name it goes by, Trim works with Active Garbage Collection to clean up and organize your solid state drive. Trim is beneficial, but not mandatory. Because some operating systems do not support Trim, SSD manufacturers design, create, and test their drives assuming that Trim will not be used.
What does Trim do?
El comando Trim le dice a la SSD que las áreas específicas contienen datos que ya no están más en uso. Desde la perspectiva del usuario, estos datos se han eliminado de un documento. Debido a la forma en que las unidades de estado sólido leen y escriben la información, los datos no se eliminan de la unidad en el comando del usuario. En su lugar, el área de la SSD que contiene los datos se marca como ya no usada. El comando Trim le dice a la unidad que se pueden eliminar los datos. La próxima vez que la computadora esté inactiva, la recolección activa de desechos borrará los datos. Obtenga más información sobre la recolección activa de desechos.
Si el comando Trim no existiera (como fue el caso antes de Windows® 7), entonces, la unidad de estado sólido no sabría que determinados sectores contienen información inválida hasta que la computadora le dijera a la unidad que escribiera nueva información en esa ubicación. La unidad tendría que eliminar la información existente y después escribir la nueva información. Esto lleva un poco más de tiempo que solo escribir nueva información, de manera que usar el Trim y la recolección activa de desechos le ayuda a que su SSD desempeñe los comandos de escritura más rápidamente.
El Trim también afecta la longevidad de la unidad de estado sólido. Si los datos se escriben y borran de las mismas celdas NAND todo el tiempo, esas celdas perderán la integridad. Para una vida óptima, cada celda deberá utilizarse aproximadamente a la misma tasa que las demás celdas. Esto se denomina nivelación de desgaste. El comando Trim le dice a la SSD qué celdas se pueden eliminar durante el tiempo de inactividad, lo que también permite que la unidad se organice las celdas llena de los datos restantes y que se escriba en las celdas vacías para evitar el borrado y la reescritura innecesarios.
How Active Garbage Collection works
Flash memory, which is what SSDs are made of, cannot overwrite existing data the way a hard disk drive can. Instead, solid state drives need to erase the now invalid data. The problem is that a larger unit of the memory, a block, must be erased before a smaller unit, a page, can be written. For example, if there are four pages with data in an otherwise empty block and three pages of data are deleted, the remaining page of data must be written to a new block, then all four pages in the old block can be deleted, freeing them up to be rewritten in the future.
If the drive were to not go through this process of moving valid information so that invalid information can be deleted, and instead, just keep writing new information to new pages, eventually it would fill up with data, some of it no longer valid. To prevent this, Active Garbage collection goes through the disk and moves each page of valid data to a page in another block so the block with invalid data, which has been identified with Trim, can be cleaned out.
Benefits of Trim and Active Garbage Collection
The biggest benefit of Trim is the time savings by having the solid state drive erase data while the computer is idle, rather than using extra time during a write process to remove data that is no longer valid. Because Active Garbage Collection moves related segments of data next to each other, dynamic wear leveling works more efficiently. Garbage collection and Trim work with wear leveling, an algorithm that ensures that each cell is written to and deleted from about the same number of times as all the other cells. This extends the life of the solid state drive.
SSD Trim support
Microsoft® Windows® from 7 forward supports Trim. It runs automatically in the background unless you have turned it off. You can run it manually or check that Trim is enabled by looking at the Properties of the drive, then selecting Tools, and Optimize.
MacOS® with Apple® SSDs has built-in Trim and Active Garbage Collection. Some versions of MacOS support third-party SSDs with additional software. To check to see if you have Trim support, select the Apple menu while holding down the Option key. Under System Information, scroll to the name of your storage interface under Hardware. TRIM Support will indicate either Yes or No.
Most RAID (Redundant Array of Independent Disks) setups do not support Trim, although that is changing. More RAID software supports Trim with each generation, so check your particular software.
Active Garbage Collection support
Garbage collection occurs automatically using proprietary Active Garbage Collection functionality created by the manufacturer of the solid state drive. Because garbage collection is so important to the functioning of the drive, all drives have it.
Micron makes all of its solid state drives from the silicon up, and garbage collection is a vital part of the drive. Learn more about the process to manufacture SSDs.
Conclusion
Trim and Active Garbage Collection are useful tools that can benefit the speed, function, and longevity of your SSD. But if your operating system doesn't support Trim, it's not a disaster. All Crucial SSDs are designed and tested assuming that they will be used without Trim.
©2019 Micron Technology, Inc. All rights reserved. Information, products, and/or specifications are subject to change without notice. Neither Crucial nor Micron Technology, Inc. is responsible for omissions or errors in typography or photography. Micron, the Micron logo, Crucial, and the Crucial logo are trademarks or registered trademarks of Micron Technology, Inc. Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the U.S. and/or other countries. MacOS and Apple are trademarks of Apple, Inc., registered in the United States and/or other countries. All other trademarks and service marks are the property of their respective owners.