Re: Linked directory or explicit reference

On Tue, Apr 30, 2024 at 7:00 PM Senor Cervesa <frio_cervesa(at)hotmail(dot)com>
wrote:

> Hi All;
>
> When doing an initial install of PostgreSQL on RHEL 7 or 8 derived OS via
> rpm, what are pros, cons and recommendations of these 2 procedures for
> utilizing a second disk?
>
> Secondary SSD or RAID mounted at /disk2.
>
> Option #1
>
> 1. install the rpm which creates basic user and home
> 2. Create symlink /var/lib/pgsql/15/data --> /disk2/data
> 3. initdb with no special options
>
> Or Option #2
>
> 1. install the rpm which creates basic user and home
> 2. initdb with --pgdata=/disk2/data
> Probably using included 'postgresql-12-setup' script
>
> I also link /var/lib/pgsql/data --> ../15/data so automation can
> reference postgresql.conf without knowing version (legacy stuff).
>

In my experience,The PgBackRest restore feature does not like symlinks.

> The install is automated with a bash script which handles several options
> including whether there is a second disk for DB. Scripting the install with
> or without the second disk is straight forward but I'm concerned with
> either scenario causing unforeseen differences.
>
> I don't think there's a benefit to using tablespace here but I have no
> experience with it. The systemd service is configured with a dependency on
> the disk mount so I don't think there are different risks for starting
> postgres with missing data directory.
>
> I've run postgres in both scenarios and not had any issues. I'm interested
> in comments from others on their experience using these or other options.
>
Is the mount point just "/disk2" when using "--pgdata=/disk2/data"? I've
gotten "directory not empty" errors when the mount point is
"/Database/x.y/data".