Planning an Informix Database disk layout

Hi everyone.... Can anyone advise me if there have been any articles written, and ae available on the web, about a disk layout strategy? We are in the process for planning the disk layout of a 150Gb system with 300+ tables. 1. Do we put the data into multiple DBSpaces? 2. Do we separate the indexes from the data or put the whole lot into one big pool? To further complicate matters, data is being loaded over a 2 year period on a geographical basis. This means that the data for the largest region and most highly accessed will be in the end of the tables or last extents. In an attempt to reduce the number of extents I though we could make them initially large, however in the "one large pool" scenario this would place all the initial extents on the same chunk thus channelling all the IO to the one disk and not spreading the load. The plan at this stage: RAID 1 Root DB Space Physical Logs Space Logical Logs Space No RAID Temp DB Space RAID 5 Data DB Space Index DB Space <--- has potential to be merged with Data DB Space Smart Blobs DB Space You'll notice the introduction of RAID 5 here. So, any therories, or references?