> > >From a portability standpoint, I think if we go anywhere, it would be to
> > write directly into device files representing sections of a disk.
>
> That makes sense to me. On "traditional" Unices, we could use the raw
> character device for a partition (eg /dev/rdsk/* on Solaris),
On Solaris this is (imho) the exact wrong way to do it. On Solaris you would
typically use logical volumes created with Veritas LVM.
Imho the times where you think of a raw device beeing one physical disk partition
are fortunately over, since LVM's are widespread enough.
> and on Linux we'd use /dev/raw*, which is a mapping to a specific partition
> established before PG startup.
Usually you would use a symlink to such a raw device if such a device needs to be
in /dev.
> I guess there would need to be a system table that keeps track of
> (dev, offset, size) tuples for each WAL file.
This would need to be hidden in a new smgr layer.
Andreas