I would suggest making thre of the 4 disks into a raid5 set, with
300MB reserved at the beginning of each disk for a small boot partition.
This would give you the required space, would allow any of your disks to
fail, and give you a spare to save to, so you would have a fully functional
raid while you swapped out a bad disk. This configuration would allow you
to lose up to half your disks, 2 of them, and still retain your data.  This
is what I did on one of my production servers about 4 years ago, and it's
worked great!
-Brian
On Mar 20,  4:46pm, Henry Nelson wrote:
} Subject: optimal (safest) RAID setup for 4 idendical ide disks
} I have four identical 3GB HDDs.  Six GB is more than enough space for
} what I want to do with this machine.  Originally I was thinking that
} setting up two RAID 1 (mirroring) sets would give me the greatest
} safety factor against failure of a disk, but, on the other hand, having
} a "hot spare" available also sounded like it would give good insurance.
} 
} Also, I wonder if I did pair up the 4 disks into two RAID sets, what
} would be the best physical configuration, i.e., should each set be
} master-master (or slave-slave) on the primary and secondary ide
} controllers, or should each RAID set be on the same controller?  (Or
} it doesn't make any difference at all?)
} 
} Any suggestions/advice on how to use four 3GD HDDs (total 12GB) to get
} 6GB of usable space with the maximum amount of protection against the
} failure of any one of the disks much appreciated.  Also, if you know of
} good URLs pointing to NOT-too-technical discussions on this topic please
} throw them my way.  TIA.
} 
} -- 
} henry nelson
}   WWW_HOME=http://yuba.kcn.ne.jp/~home/
>-- End of excerpt from Henry Nelson