RAID 0+1 is a mirror of stripes
For example six 250GB drives used in raid 0 to create two 750GB RAID 0 array's. Then those 750GB arrays are put into RAID 1.
RAID 1
______________________
| |
RAID 0 RAID 0
_____________ _____________
| | | | | |
250GB 250GB 250GB 250GB 250GB 250GB
A1 A2 A3 A1 A2 A3
A4 A5 A6 A4 A5 A6
A7 A8 A9 A7 A8 A9
A10 A11 A12 A10 A11 A12
RAID 10 is a stripe of mirrors
Six 250GB disks in three mirrored pairs then put into a RAID 0 array to achieve 750GB disk.
RAID 0
_______________________________
| | |
RAID 1 RAID 1 RAID 1
_______ _______ _______
| | | | | |
250GB 250GB 250GB 250GB 250GB 250GB
A1 A1 A2 A2 A3 A3
A4 A4 A5 A5 A6 A6
A7 A7 A8 A8 A9 A9
A10 A10 A11 A11 A12 A12
Raid 0+1 will generally have better write performance, where Raid 10 will have better read performance. But even that isn't absolute as it depends on what type of hard drives you're using, the controller and the actual file sizes that would be transfered/accessed.
ULTRA 160/320 SCSI disks have better performance with small files, thus are better suited for web servers, data servers, or even just your OS swap file. SCSI of course has the added benifit of being able to have 16 drives attached to one controller, though there is still the max transfer speed of 160/320 MB/s on the raid controller whether it be a single channel RAID card with 16 disks, or 8 channel card with 2 disks per channel.
Sata drives are better suited for large files, uncompressed photos, Video files, disc images etc. With sata there is the added benifit of 150 MB/s - 300 MB/s theoretical transfer per channel, and since most of us haven't adapted the SATA splitter hubss it's a safe bet you won't have to worry about transfer bottleneck with a single disk per channel.
However now that technology has caught up a bit, RAID 5 is actually the best performance/data security solution. Only drawback being that you need a good raid card to be able to pull off RAID 5 without it having huge system overhead, but still more worth it imo. RAID 5 really doesn't have a disk limit for an array anymore as far as i know, and for example if you have 7 disks in RAID 5, you only lose one disk worth of storage capacity to redundancy data....well that's true whether you have 4 disks or 16.
My media server is set up with 7, 74GB 10k RPM 16MB cache SCSI disks in RAID 5 for storing application data and the like, with 4, 500GB SATA II disks in Raid 10 for video files and disc image back ups. I'll be adding another rack of 74GB SCSI's in the next week or so, to get 900 Gigs of Raid 5 SCSI storage and 1 terabyte of SATA sorage. Sata performance is 50-65 mb/s disk performance over a gigabyte ethernet line, the SCSI performance is equivolent on network, and 90 MB/s or so sustained performance moving files internally.