From: Martin Steigerwald <martin@lichtvoll.de>
To: Hugo Mills <hugo@carfax.org.uk>, linux-btrfs@vger.kernel.org
Subject: Re: Small fs
Date: Sun, 11 Sep 2016 21:51:38 +0200 [thread overview]
Message-ID: <34273168.IdA9o4YR3V@merkaba> (raw)
In-Reply-To: <20160911194632.GF7138@carfax.org.uk>
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
next prev parent reply other threads:[~2016-09-11 19:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-11 15:27 Small fs Imran Geriskovan
2016-09-11 15:32 ` Martin Steigerwald
2016-09-11 16:44 ` Duncan
2016-09-11 18:56 ` Imran Geriskovan
2016-09-11 19:21 ` Martin Steigerwald
2016-09-12 12:41 ` Austin S. Hemmelgarn
2016-09-12 14:09 ` Henk Slager
2016-09-12 14:12 ` Austin S. Hemmelgarn
2016-09-12 14:51 ` Chris Murphy
2016-09-12 14:56 ` Austin S. Hemmelgarn
2016-09-12 3:33 ` Duncan
2016-09-12 14:11 ` Imran Geriskovan
2016-09-12 17:43 ` Imran Geriskovan
2016-09-12 18:46 ` Imran Geriskovan
2016-09-12 18:55 ` Austin S. Hemmelgarn
2016-09-12 21:32 ` Mike Fleetwood
2016-09-11 19:13 ` Martin Steigerwald
2016-09-11 19:46 ` Hugo Mills
2016-09-11 19:51 ` Martin Steigerwald [this message]
2016-09-12 12:45 ` Austin S. Hemmelgarn
2016-09-11 20:33 ` Chris Murphy
2016-09-12 2:00 ` Duncan
2016-09-12 3:03 ` Chris Murphy
2016-09-12 4:54 ` Duncan
2016-09-12 14:48 ` Chris Murphy
2016-09-13 4:25 ` Duncan
2016-09-12 12:54 ` Imran Geriskovan
2016-09-12 13:01 ` Austin S. Hemmelgarn
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