Re: pg_xlog safety

Andrew Sullivan wrote:
> On Sun, Jan 26, 2003 at 05:26:15PM -0500, Bruce Momjian wrote:
> >
> > If you raid has battery-backed RAM cach in your controller, there is no
> > advantage to putting WAL on a separate disk --- was that the case?
>
> That was always my view, as well.  But someone presented me with an
> argument that it would somehow be better to use separate disks inside
> the array in order to make this faster (i.e. it'd still be faster
> because there'd be no contention for spindles).  So, I tried it, but
> I could see no difference no matter what I did.

With battery-backed RAM, you would have to fill up that cache faster
than it can flush it (at its leasure) to the disk.  It would take a heck
of a lot of activity to cause that.

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