Re: PostgreSQL on S3-backed Block Storage with Near-Local Performance

Hi all,

Building on that, I made Postgres run in the browser using a x86 JavaScript emulator, with ZeroFS mounted in that vm through vsock-virtio that channels back to a 9P websocket wrapper: https://www.zerofs.net/postgresql-in-the-browser

Best,
Pierre

On Mon, Feb 16, 2026, at 12:06, Pierre Barre wrote:
> Hi all,
>
> Circling back on this thread, ZeroFS now supports placing its WAL on
> local storage (or something like S3 Express One Zone). ZeroFS wal is
> sub-gigabyte and just there to handle frequent syncs, it doesn't act as
> writeback caching.
>
> Here are pgbench results with synchronous_commit = on, WAL on local
> NVMe, on a 6-core / 32GB RAM machine with a 4 Gb/s pipe:
>
> $ pgbench -c 100 -T 100 --protocol=prepared
>
> transaction type: <builtin: TPC-B (sort of)>
> scaling factor: 100
> query mode: prepared
> number of clients: 100
> number of threads: 1
> duration: 100 s
> number of transactions actually processed: 1,578,675
> number of failed transactions: 0 (0.000%)
> latency average = 6.312 ms
> tps = 15,843 (without initial connection time)
>
> Best,
> Pierre
>
> On Fri, Jul 25, 2025, at 00:03, Jeff Ross wrote:
>> On 7/24/25 13:50, Pierre Barre wrote:
>>
>>> It’s not “safe” or “unsafe”, there’s mountains of valid workloads which don’t require synchronous_commit. Synchronous_commit don’t make your system automatically safe either, and if that’s a requirement, there’s many workarounds, as you suggested, it certainly doesn’t make the setup useless.
>>>
>>> Best,
>>> Pierre
>>>
>>> On Thu, Jul 24, 2025, at 21:44, Nico Williams wrote:
>>>> On Fri, Jul 18, 2025 at 12:57:39PM +0200, Pierre Barre wrote:
>>>>> - Postgres configured accordingly memory-wise as well as with
>>>>> synchronous_commit = off, wal_init_zero = off and wal_recycle = off.
>>>> Bingo. That's why it's fast (synchronous_commit = off). It's also why
>>>> it's not safe _unless_ you have a local, fast, persistent ZIL device
>>>> (which I assume you don't).
>>>>
>>>> Nico
>>>> --
>> This then begs the obvious question of how fast is this with
>> synchronous_commit = on?