From: Freddie Cash <fjwcash@gmail.com>
To: Alan Chandler <alan@chandlerfamily.org.uk>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Synching a Backup Server
Date: Sun, 9 Jan 2011 09:59:46 -0800 [thread overview]
Message-ID: <AANLkTim96P3ZD-WpDonsOHB7aicNBQX-wK6v347r1z8s@mail.gmail.com> (raw)
In-Reply-To: <4D29D508.6080006@chandlerfamily.org.uk>
On Sun, Jan 9, 2011 at 7:32 AM, Alan Chandler
<alan@chandlerfamily.org.uk> wrote:
> I think I start to get it now. =C2=A0Its the fact that subvolumes can=
be
> snapshotted etc without mounting them that is the difference. =C2=A0I=
guess I am
> too used to thinking like LVM and I was thinking subvolumes where lik=
e an
> LV. =C2=A0They are, but not quite the same.
Let see if I can match up the terminology and layers a bit:
LVM Physical Volume =3D=3D Btrfs disk =3D=3D ZFS disk / vdevs
LVM Volume Group =3D=3D Btrfs "filesystem" =3D=3D ZFS storage pool
LVM Logical Volume =3D=3D Btrfs subvolume =3D=3D ZFS volume
'normal' filesysm =3D=3D Btrfs subvolume (when mounted) =3D=3D ZFS file=
system
Does that look about right?
LVM: A physical volume is the lowest layer in LVM and they are
combined into a volume group which is then split up into logical
volumes, and formatted with a filesystem.
Btrfs: A bunch of disks are "formatted" into a btrfs "filesystem"
which is then split up into sub-volumes (sub-volumes are
auto-formatted with a btrfs filesystem).
ZFS: A bunch of disks are combined into virtual devices, then combined
into a ZFS storage pool, which can be split up into either volumes
formatted with any filesystem, or ZFS filesystems.
Just curious, why all the new terminology in btrfs for things that
already existed? And why are old terms overloaded with new meanings?
I don't think I've seen a write-up about that anywhere (or I don't
remember it if I have).
Perhaps it's time to start looking at separating the btrfs pool
creation tools out of mkfs (or renaming mkfs.btrfs), since you're
really building a a storage pool, and not a filesystem. It would
prevent a lot of confusion with new users. It's great that there's a
separate btrfs tool for manipulating btrfs setups, but "mkfs.btrfs" is
just wrong for creating the btrfs setup.
--=20
=46reddie Cash
fjwcash@gmail.com
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" =
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2011-01-09 17:59 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-06 17:35 Synching a Backup Server Carl Cook
2011-01-06 19:16 ` Freddie Cash
2011-01-06 19:34 ` Marcin Kuk
[not found] ` <AANLkTik-rhXAHW18id4WMMtdqXkicvzTZ47+2r6YMuY0@mail.gmail.com>
2011-01-06 19:47 ` Freddie Cash
2011-01-06 20:07 ` C Anthony Risinger
2011-01-06 20:13 ` Freddie Cash
2011-01-06 20:21 ` C Anthony Risinger
2011-01-06 21:06 ` Gordan Bobic
2011-01-06 21:39 ` Freddie Cash
2011-01-06 21:44 ` Carl Cook
2011-01-06 21:53 ` Gordan Bobic
2011-01-06 21:58 ` Freddie Cash
2011-01-06 22:26 ` Carl Cook
2011-01-06 22:29 ` Gordan Bobic
2011-01-06 23:07 ` Carl Cook
2011-01-07 16:14 ` Hubert Kario
2011-01-06 23:15 ` Fajar A. Nugraha
2011-01-06 21:42 ` Carl Cook
2011-01-06 21:52 ` Freddie Cash
2011-01-07 16:20 ` Hubert Kario
2011-01-09 11:46 ` Alan Chandler
2011-01-09 13:54 ` Fajar A. Nugraha
2011-01-09 15:32 ` Alan Chandler
2011-01-09 17:59 ` Freddie Cash [this message]
2011-01-09 18:30 ` Hugo Mills
2011-01-09 20:57 ` Alan Chandler
2011-01-09 22:01 ` Hugo Mills
2011-01-09 23:32 ` Alan Chandler
2011-01-11 22:25 ` Hugo Mills
2011-01-10 2:22 ` Fajar A. Nugraha
2011-01-11 22:41 ` Hugo Mills
2011-01-21 19:28 ` Freddie Cash
2011-01-22 13:45 ` Hugo Mills
2011-01-24 17:45 ` Freddie Cash
2011-01-22 13:55 ` Hubert Kario
2011-01-25 17:29 ` Kaspar Schleiser
2011-01-25 17:43 ` Hubert Kario
2011-01-25 17:59 ` Freddie Cash
2011-01-25 18:36 ` Hubert Kario
2011-01-10 13:14 ` Hubert Kario
2011-01-06 20:12 ` Fajar A. Nugraha
2011-01-06 21:43 ` Carl Cook
2011-01-06 21:43 ` Goffredo Baroncelli
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=AANLkTim96P3ZD-WpDonsOHB7aicNBQX-wK6v347r1z8s@mail.gmail.com \
--to=fjwcash@gmail.com \
--cc=alan@chandlerfamily.org.uk \
--cc=linux-btrfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).