Re: Tuning PostgreSQL

On Tue, Jul 22, 2003 at 11:40:35 +0200,
  Vincent van Leeuwen <pgsql.spam@vinz.nl> wrote:
>
> About RAID types: the fastest RAID type by far is RAID-10. However, this will
> cost you a lot of useable diskspace, so it isn't for everyone. You need at
> least 4 disks for a RAID-10 array. RAID-5 is a nice compromise if you want as
> much useable diskspace as possible and still want to be redundant. RAID-1 is
> very useful for small (2-disk) arrays.

Note that while raid 10 requires 4 disks, you get the space of 2 disks.
This is the same ratio as for raid 1.