Jeff Moyer wrote: > James Bottomley <James.Bottomley@xxxxxxx> writes: > > > Not stepping into the debate: I'm happy to see punch go to the mapping > > data and FITRIM pick it up later. > > > > However, I think it's time to question whether we actually still want to > > allow online discard at all. Most of the benchmarks show it to be a net > > Define online discard, please. > > > lose to almost everything (either SSD or Thinly Provisioned arrays), so > > it's become an "enable this to degrade performance" option with no > > upside. > > Some SSDs very much require TRIMming to perform well as they age. If > you're suggesting that we move from doing discards in journal commits to > a batched discard, like the one Lukas implemented, then I think that's > fine. If we need to reintroduce the finer-grained discards due to some > hardware changes in the future, we can always do that. "Growable" virtual disks benefit from it too, if it frees up a lot of space. Windows has some ability to trim unused space in NTFS on virtual disks for this reason; I'm not sure if it's an online or offline procedure. Online trim may be slow, but offline would be awfully inconvenient when an fs is big and needed for a live system, or when it's your root fs. -- Jamie -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
