Am Sonntag, 11. September 2016, 19:46:32 CEST schrieb Hugo Mills: > On Sun, Sep 11, 2016 at 09:13:28PM +0200, Martin Steigerwald wrote: > > Am Sonntag, 11. September 2016, 16:44:23 CEST schrieb Duncan: > > > * Metadata, and thus mixed-bg, defaults to DUP mode on a single-device > > > filesystem (except on ssd where I actually still use it myself, and > > > recommend it except for ssds that do firmware dedupe). In mixed-mode > > > this means two copies of data as well, which halves the usable space. > > > > > > IOW, when using mixed-mode, which is recommended under a gig, and dup > > > replication which is then the single-device default, effective usable > > > space is **HALVED**, so 256 MiB btrfs size becomes 128 MiB usable. (!!) > > > > I don´t get this part. That is just *metadata* being duplicated, not the > > actual *data* inside the files. Or am I missing something here? > > In mixed mode, there's no distinction: Data and metadata both use > the same chunks. If those chunks are DUP, then both data and metadata > are duplicated, and you get half the space available.
In german I´d say "autsch", in english according to pda.leo.org "ouch", to this. Okay, I just erased using mixed mode as an idea from my mind altogether :). Just like I think I will never use a BTRFS below 5 GiB. Well, with one exception, maybe on the eMMC flash of the new Omnia Turris router that I hope will arrive soon at my place. -- Martin -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
