From: Roman Mamedov <rm@romanrm.net>
To: Adam Borowski <kilobyte@angband.pl>
Cc: Christoph Anton Mitterer <calestyo@scientia.net>,
"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: zerofree btrfs support?
Date: Sat, 10 Mar 2018 23:31:27 +0500 [thread overview]
Message-ID: <20180310233127.0dfa7823@natsu> (raw)
In-Reply-To: <20180310155022.wtdmwiyxu7mxt74s@angband.pl>
On Sat, 10 Mar 2018 16:50:22 +0100
Adam Borowski <kilobyte@angband.pl> wrote:
> Since we're on a btrfs mailing list, if you use qemu, you really want
> sparse format:raw instead of qcow2 or preallocated raw. This also works
> great with TRIM.
Agreed, that's why I use RAW. QCOW2 would add a second layer of COW on top of
Btrfs, which sounds like a nightmare. Even if you would run those files as
NOCOW in Btrfs, somehow I feel FS-native COW is more efficient than emulating
it in userspace with special format files.
> > It works, just not with some of the QEMU virtualized disk device drivers.
> > You don't need to use qemu-img to manually dig holes either, it's all
> > automatic.
>
> It works only with scsi and virtio-scsi drivers. Most qemu setups use
> either ide (ouch!) or virtio-blk.
It works with IDE as well.
--
With respect,
Roman
next prev parent reply other threads:[~2018-03-10 18:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-10 2:55 zerofree btrfs support? Christoph Anton Mitterer
2018-03-10 8:16 ` Adam Borowski
2018-03-10 14:19 ` Christoph Anton Mitterer
2018-03-10 14:37 ` Roman Mamedov
2018-03-10 15:50 ` Adam Borowski
2018-03-10 16:58 ` Christoph Anton Mitterer
2018-03-10 18:31 ` Roman Mamedov [this message]
2018-03-10 18:39 ` Christoph Anton Mitterer
2018-03-10 16:55 ` Christoph Anton Mitterer
2018-03-14 19:38 ` David Sterba
2018-03-15 2:54 ` Christoph Anton Mitterer
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=20180310233127.0dfa7823@natsu \
--to=rm@romanrm.net \
--cc=calestyo@scientia.net \
--cc=kilobyte@angband.pl \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.