Re: Postgres on L2ARC

> On Jan 23, 2023, at 6:18 PM, Joseph Hammerman <joe(dot)hammerman(at)datadoghq(dot)com> wrote:
>
> Has anyone built a Postgers architecture using L2ARC, and potentially TABLESPACES to mount the ZFS pools (dedicated one per table). I am imagining the ZFS pools would be backed by EBS volumes.

Yes. It worked fine, but much smaller and less busy than what you're probably planning for. Originally, Ubuntu 16 & older ZFS, PG data was on mirrorz SSD, with other SSD partitions for L2ARC & ZIL. Later, at a major update, I did some benchmarking, and got rid of the SSD dedicated to ZFS. Then the SSD became entirely ZIL & L2ARC, and PG shared L2ARC with other data.

So, to be clear, in this case the reason for having PG use L2ARC with spinning rust behind it was that the PG did not need dedicated SSD for performance...