From: Christoph Hellwig <hch@lst.de>
To: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: linux-btrfs@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Damien Le Moal <dlemoal@kernel.org>,
Naohiro Aota <naohiro.aota@wdc.com>,
Hans Holmberg <Hans.Holmberg@wdc.com>,
David Sterba <dsterba@suse.com>, Qu Wenruo <wqu@suse.com>
Subject: Re: [PATCH RFC 0/1] btrfs: don't allocate data off of conventional zones
Date: Fri, 16 Jan 2026 15:54:21 +0100 [thread overview]
Message-ID: <20260116145421.GC16842@lst.de> (raw)
In-Reply-To: <20260116095739.44201-1-johannes.thumshirn@wdc.com>
On Fri, Jan 16, 2026 at 10:57:36AM +0100, Johannes Thumshirn wrote:
> On a zoned filesystem allocate data block-groups only off of the
> sequential zones of a device.
>
> Doing so will free up the conventional zones for the system and metadata
> block-groups, eventually removing the need for using the zoned allocator
> and all it's required infrastructure, that needs to be emulated, for
> conventional zones.
>
> TODO: If the device does not have any sequential zones left, but
> conventional, allocate the data block-group from the conventional zone,
> or just ENOSPC?
How likely is that? Given that amount of metadata btrfs has I'd be
more worried about the inverse: running out of conventional zones for
metadata. Did you or anyone do a rough calculation of how much
metadata you need relative to the data for various scenarios (small
files, large files, lots of snapshots, etc)?
Keeping the pools entirely separate is of course much easier, but it
has to work out, and having allowed to combined them before might
have set expectations as well unfortunately.
next prev parent reply other threads:[~2026-01-16 14:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-16 9:57 [PATCH RFC 0/1] btrfs: don't allocate data off of conventional zones Johannes Thumshirn
2026-01-16 9:57 ` [PATCH RFC 1/1] btrfs: zoned: only allocate data off of sequential zones Johannes Thumshirn
2026-01-16 9:57 ` [PATCH RFC 1/2] btrfs-progs: collapse find_free_dev_extent into find_free_dev_extent_start Johannes Thumshirn
2026-01-16 9:57 ` [PATCH RFC 2/2] btrfs-progs: zoned: only allocate data off of sequential zones Johannes Thumshirn
2026-01-16 14:54 ` Christoph Hellwig [this message]
2026-01-16 18:46 ` [PATCH RFC 0/1] btrfs: don't allocate data off of conventional zones Johannes Thumshirn
2026-01-17 9:46 ` Johannes Thumshirn
2026-01-19 6:48 ` hch
2026-01-19 6:50 ` hch
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=20260116145421.GC16842@lst.de \
--to=hch@lst.de \
--cc=Hans.Holmberg@wdc.com \
--cc=dlemoal@kernel.org \
--cc=dsterba@suse.com \
--cc=johannes.thumshirn@wdc.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=naohiro.aota@wdc.com \
--cc=wqu@suse.com \
/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