On Fr, 20.12.19 18:11, Louis Lagendijk (louis@xxxxxxxxxx) wrote: > On Fri, 2019-12-20 at 17:46 +0100, Lennart Poettering wrote: > > > > Or let me ask this differently: the "discard" mount option of various > > kernel file systems, what does it differently than what this new > > fedora feature is supposed to do? > > > fstrim does the discard once a week (or whenever it it triggered), > discard as a mount option does trigger discard when a block is freed. > Depending on the drive it may actually slow down IO as the SSD will > need more time to finish the IO. Doing an fstrim leaves the processing > to the SDD. That was the argument years ago. I don't know if this is Hmm? if the if the fs enqeues the trimming or userspace does, it's always the SSD that executes it... > still true for modern SSD's. For older SSDs fstrim would stil be the > safer option. And automatic trimming is long overdue in my opinion. So if trimming is slow, that's still no reason to let userspace pick a time for it. Sounds like the kernel fs should have discard=lazy or discard=5min or so. Which would enqueue a trim run automatically after the last IO after some delay. Still not grokking why to do this in userspace. -- Lennart Poettering, Berlin _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
