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
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