On 08/05/2013 12:46 AM, Ingo Weinhold wrote:
On 08/05/2013 12:30 AM, axeld-github.trim wrote:be4f73b: Added fstrim command. Later, there should be a service that runs this from time to time for all devices that support it.That seems a bit crude. Wouldn't it be preferable to do the trimming on-the-fly as needed? I.e. when a file is removed the file system should know which blocks can be trimmed. If this is problematic with respect to performance a service could be provided to buffer the trim requests.
This is actually how Linux does it which I figure is good enough for us :-)Linux also supports discarding the blocks directly, but that seems to have a great impact on file system speed. At least the numbers I found on the net seems to suggest that, see for example [1], respectively the links found in there [2], [3].
Buffering the blocks to be trimmed is problematic, as you will need to check whether they are still available when you get to trim them, plus this info won't survive a reboot.
Do you have a better idea in this light? Bye, Axel.[1] http://blog.neutrino.es/2013/howto-properly-activate-trim-for-your-ssd-on-linux-fstrim-lvm-and-dmcrypt/
[2] https://patrick-nagel.net/blog/archives/337 [3] http://oss.sgi.com/pipermail/xfs/2011-November/015320.html
