Re: Real application clustering in postgres.

On Sun, 2020-03-08 at 21:13 +0100, Peter J. Holzer wrote:
> But to be fair, a master/slave setup a la patroni isn't immune against
> "writing junk" either: Not on the hardware level (either of the nodes
> may have faulty hardware, and you may not notice it until too late), and
> more importantly, not on the software level. An erroneus DML statement
> (because of a bug in the application, or because the user/admin made a
> mistake) will cause the same wrong data to be distributed to all nodes
> (of course this also applies to RAC).

Of course, nobody debates that.

A high-availability solution only protects you from certain, well-defined
kinds of problems, usually related to hardware.

There is no way to protect yourself from software bugs or user errors.

If there is a hardware problem that causes one of the databases in the
Patroni cluster to become corrupted, the others are not immediately
affected.  That's the point of a shared-nothing architecture.

Of course, if the corrupted database is the primary, corruption can
eventually spread to the others.

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com