Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> *scratches head*
>
> I don't really know how you COULD pick a safe default location.
> Presumably any location that's in the default postgresql.conf file
> would be under $PGDATA, which kind of defeats the purpose of the
> whole thing. In other words, you're always going to have to move it
> anyway, so why bother with a default that is bound to be wrong?
Well, we want the WAL files to flow in two directions from the
database server so that if either target (or connectivity to it) is
down, the WAL files still flow to the other target. The only sensible
way to do that, as far as we've determined, is to have the archive
script copy to a temporary directory and move to a "publisher"
directory, then have once-a-minute crontab jobs to rsync the directory
to the targets.
We figure that while a WAL file is not more at risk in the publisher
directory than in the pg_xlog directory on the same volume.
The other reason is what I think Greg Smith was mentioning --
simplifying the process of grabbing a usable PITR backup for novice
users. That seems like it has merit.
-Kevin