Michael Stone <mstone+postgres@mathom.us> writes:
> it is possible to have a mirror of more than two disks (which would have the
> same read advantage as the striped configuration with the same number of
> disks) but this is rarely seen because it is expensive.
Actually three-way mirrors are quite common for backup purposes. To take a
backup you break the mirror by taking one of the three copies out. Back it up
at your leisure, then just resync it in time for the next backup.
--
greg