On Thu, Dec 29, 2011 at 11:02 AM, Li Zefan <lizf@xxxxxxxxxxxxxx> wrote: > Martin Steigerwald wrote: >> With 3.2-rc4 (probably earlier), Ext4 seems to remember what areas it >> trimmed: >> But BTRFS does not: > There's no such plan, but it's do-able, and I can take care of it. > There's an issue though. > For btrfs this issue can't be solved without disk format change that > will break older kernels, but only 3.2-rcX kernels will be affected if > we push the following change into mainline before 3.2 release. Slightly off-topic, how useful would trim be for btrfs when using newer SSD which have their own garbage collection and wear leveling (e.g. sandforce-based)? I'm trying fstrim and my disk is now pegged at write IOPS. Just wondering if maybe a "btrfs fi balance" would be more useful, since: - with trim, used space will remain used. Thus future writes will only utilized space marked as "free", making them wear faster - with "btrfs fi balance", btrfs will move the data around so (to some degree) the currently-unused space will be used, and currently-used space will be unused, which will improve wear leveling. -- Fajar -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
