Re: [LSF/MM/BPF TOPIC]: File system data placement for zoned block devices

From: Hans Holmberg <hans@owltronix.com>
To: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Cc: "Hans Holmberg" <Hans.Holmberg@wdc.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"jaegeuk@kernel.org" <jaegeuk@kernel.org>,
	"josef@toxicpanda.com" <josef@toxicpanda.com>,
	"Matias Bjørling" <Matias.Bjorling@wdc.com>,
	"Damien Le Moal" <Damien.LeMoal@wdc.com>,
	"Dennis Maisenbacher" <dennis.maisenbacher@wdc.com>,
	"Naohiro Aota" <Naohiro.Aota@wdc.com>,
	"Aravind Ramesh" <Aravind.Ramesh@wdc.com>,
	"Jørgen Hansen" <Jorgen.Hansen@wdc.com>,
	"mcgrof@kernel.org" <mcgrof@kernel.org>,
	"javier@javigon.com" <javier@javigon.com>,
	"hch@lst.de" <hch@lst.de>,
	"a.manzanares@samsung.com" <a.manzanares@samsung.com>,
	"guokuankuan@bytedance.com" <guokuankuan@bytedance.com>,
	"viacheslav.dubeyko@bytedance.com"
	<viacheslav.dubeyko@bytedance.com>,
	"j.granados@samsung.com" <j.granados@samsung.com>,
	"Boris Burkov" <boris@bur.io>
Subject: Re: [LSF/MM/BPF TOPIC]: File system data placement for zoned block devices
Date: Tue, 7 Feb 2023 13:31:44 +0100	[thread overview]
Message-ID: <CANr-nt2q-1GjE6wx4W+6cSV9RULd8PKmS2-qyE2NvhRgMNawXQ@mail.gmail.com> (raw)
In-Reply-To: <22843ea8-1668-85db-3ba3-f5b4386bba38@wdc.com>

On Mon, Feb 6, 2023 at 3:24 PM Johannes Thumshirn
<Johannes.Thumshirn@wdc.com> wrote:
>
> On 06.02.23 14:41, Hans Holmberg wrote:
> > Out of the upstream file systems, btrfs and f2fs supports
> > the zoned block device model. F2fs supports active data placement
> > by separating cold from hot data which helps in reducing gc,
> > but there is room for improvement.
>
> FYI, there's a patchset [1] from Boris for btrfs which uses different
> size classes to further parallelize placement. As of now it leaves out
> ZNS drives, as this can clash with the MOZ/MAZ limits but once active
> zone tracking is fully bug free^TM we should look into using these
> allocator hints for ZNS as well.
>

That looks like a great start!

Via that patch series I also found Josef's fsperf repo [1], which is
exactly what I have
been looking for: a set of common tests for file system performance. I hope that
it can be extended with longer-running tests doing several disk overwrites with
application-like workloads.

> The hot/cold data can be a 2nd placement hint, of cause, not just the
> different size classes of an extent.

Yes. I'll dig into the patches and see if I can figure out how that
could be done.

Cheers,
Hans

[1] https://github.com/josefbacik/fsperf