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Date: Fri, 18 Jul 2025 11:59:18 +0200
From: "Pierre Barre" <pierre@barre.sh>
To: "Laurenz Albe" <laurenz.albe@cybertec.at>,
 pgsql-general@lists.postgresql.org
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 <3345416f84147603587ff8656cc3ac95b6787744.camel@cybertec.at>
Subject: Re: PostgreSQL on S3-backed Block Storage with Near-Local Performance
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Hi Laurenz,

> I think the biggest hurdle you will have to overcome is to
> convince notoriously paranoid DBAs that this tall stack
> provides reliable service, honors fsync() etc.

Indeed, but that doesn't have to be "sudden." I think we need to gain co=
nfidence in the whole system gradually by starting with throwable worklo=
ads (e.g., persistent volumes in CI), then moving to data we can afford =
to lose, then backups, and finally to production data.

>> P.S. The full project includes a custom NFS filesystem too.
>
> "NFS" is a key word that does not inspire confidence in
> PostgreSQL circles...

I've had my fair share of major annoyances with NFS too!

I think bad experiences with NFS are basically due to the fact that when=
 the hardware is bad, the NFS server implementation is bad, and the kern=
el treats it mostly like a "local" filesystem (in terms of failure behav=
ior).=20

So when it doesn't work well, everything goes down.

But the protocols themselves are not inherently bad=E2=80=94they are act=
ually quite elegant. NFSv3 is just what you need to reach (very close to=
) POSIX compliance. The NFS server implementation in ZeroFS passes all 8=
,662 tests in https://github.com/Barre/pjdfstest_nfs.

https://github.com/Barre/ZeroFS/actions/runs/16367571315/job/46248240251=
#step:11:9376

For database workloads specifically, users will probably prefer running =
something like ZFS on top of the NBD server rather than using NFS direct=
ly.

Best,
Pierre

On Fri, Jul 18, 2025, at 06:40, Laurenz Albe wrote:
> On Fri, 2025-07-18 at 00:57 +0200, Pierre Barre wrote:
>> Looking forward to your feedback and questions!
>
> I think the biggest hurdle you will have to overcome is to
> convince notoriously paranoid DBAs that this tall stack
> provides reliable service, honors fsync() etc.
>
> Performance is great, but it is not everything.  If things
> perform surprisingly well, people become suspicious.
>
>> P.S. The full project includes a custom NFS filesystem too.
>
> "NFS" is a key word that does not inspire confidence in
> PostgreSQL circles...
>
> Yours,
> Laurenz Albe