Ulrik S. Kofod wrote:
I have 3 disks that I want to setup in a raid 1, my questions is should I setup the 3rd disk as a spare-disk or should I mirror all 3 disks all the time?
Will it perform *much* better to only mirror two and have the 3rd as a spare. Is it not safer to mirror all 3 drives all the time ?
I really don't understand the question. RAID-1 requires an even number of disks since disk(s) A simply is a mirror image of disk(s) B. So with 3 disks you could have a 2-drive mirror and designate the 3rd drive as a hot spare. So if one of your mirrored drives fails, the hot spare takes over. You could just as easily do a 3-disk RAID-5 array. It would be substantially faster on reads than a 2-disk mirror. It could be faster or slower on writes depending on which hardware RAID card you're using or how fast your processor is if you're doing software RAID.
Cheers,