Re: Postgres, fsync, and OSs (specifically linux)

Hi,

On 2018-04-28 17:35:48 +0200, Michael Banck wrote:
> This dmesg-checking has been mentioned several times now, but IME
> enterprise distributions (or server ops teams?) seem to tighten access
> to dmesg and /var/log to non-root users, including postgres.
>
> Well, or just vanilla Debian stable apparently:
>
> postgres(at)fock:~$ dmesg
> dmesg: read kernel buffer failed: Operation not permitted
>
> Is it really a useful expectation that the postgres user will be able to
> trawl system logs for I/O errors? Or are we expecting the sysadmins (in
> case they are distinct from the DBAs) to setup sudo and/or relax
> permissions for this everywhere? We should document this requirement
> properly at least then.

I'm not a huge fan of this approach, but yes, that'd be necessary. It's
not that problematic to have to change /dev/kmsg permissions imo. Adding
a read group / acl seems quite doable.

> The netlink thing from Google that Tet Ts'O mentioned would probably
> work around that, but if that is opened up it would not be deployed
> anytime soon either.

Yea, that seems irrelevant for now.

Greetings,

Andres Freund