SSDs introduced fast reads and writes compared with HDDs, but quickly showed considerable performance degradation after short use. Existing operating systems did not work correctly with SSD controllers: instead of writing zeroes to empty blocks, they marked whole blocks as deleted. Because SSDs write blocks of a fixed size, this meant reading the area again, modifying it (writing zeroes), then writing the data.
What is TRIM and how does it work?
TRIM was originally developed for Linux to protect SSDs, whose cells have limited write endurance. It tracks how often cells have been rewritten and favours cells with fewer rewrites. TRIM is an ATA-standard command communicating free-cell information directly to the SSD controller to extend its lifetime.
TRIM requires both a supported operating system and an SSD controller supporting TRIM.
Operating systems supporting TRIM:
- Windows 7
- Windows Server 2008 R2
- Linux 2.6.33
- OpenSolaris 6/2010
- FreeBSD 8.1
- DragonFly BSD 5/2011
- Mac OS X Snow Leopard v10.6.6
- Mac OS X Lion v10.7
How can you check whether TRIM is enabled?
Open an administrator command prompt (CMD) and enter:
fsutil behavior query disabledeletenotify
- DisableDeleteNotify = 0 – TRIM is enabled
- DisableDeleteNotify = 1 – TRIM is disabled
Komentáře