Re: Tuning Linux for Postgresql - Database failed to start

> On May 10, 2022, at 2:23 PM, Albin Ary <albinary10(at)gmail(dot)com> wrote:
>
> Hello,
> I have a Postgresql Database cluster.
> Version: 14.2
> OS: Oracle Linux 8
>
> I tried to follow the link to optimize the server.
> https://www.enterprisedb.com/blog/tuning-red-hat-enterprise-linux-family-postgresql
>
> Unfortunately, after rebooting the database is not starting anymore. I know the HINT is straightforward but I am not able to see what the reason could be.
>
> Any advice would be appreciated.
>
> -- Unit postgresql-14.service has begun starting up.
> May 10 22:10:40 postgersdb.localdomain postmaster[1612]: 2022-05-10 22:10:40.047 CEST [1612] FATAL: could not map anonymous shared memory: Cannot allocate memory
> May 10 22:10:40 postgersdb.localdomain postmaster[1612]: 2022-05-10 22:10:40.047 CEST [1612] HINT: This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory,>
> May 10 22:10:40 postgersdb.localdomain postmaster[1612]: 2022-05-10 22:10:40.048 CEST [1612] LOG: database system is shut down
> May 10 22:10:40 postgersdb.localdomain systemd[1]: postgresql-14.service: Main process exited, code=exited, status=1/FAILURE
> May 10 22:10:40 postgersdb.localdomain systemd[1]: postgresql-14.service: Failed with result 'exit-code'.
> -- Subject: Unit failed
> -- Defined-By: systemd
> -- Support: https://support.oracle.com

This is a decent quick guide to the parameters affecting this:

https://docs.oracle.com/cd/E19879-01/821-0182/fxxua/index.html

And here is the explanation as to how they related to postgres:

https://www.postgresql.org/docs/14/kernel-resources.html