Обсуждение: Postgres on L2ARC

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Postgres on L2ARC

От
Joseph Hammerman
Дата:
Hi pgsql admins,

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.

Theoretically this seems like it would map well to a random read workload, make it possible to organically grow the devices by adding new RAID volumes, and help make the individual nodes more "stateless".

Thanks in advance for any insight or guidance anyone can providence on this matter,
Joe

Re: Postgres on L2ARC

От
Scott Ribe
Дата:
> On Jan 23, 2023, at 6:18 PM, Joseph Hammerman <joe.hammerman@datadoghq.com> wrote:
>
> Has anyone built a Postgers architecture using L2ARC, and potentially TABLESPACES to mount the ZFS pools (dedicated
oneper 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 &
olderZFS, 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
withother 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
needdedicated SSD for performance...