Question about hard drive and raid speed

For your application you will get almost no speed improvement with RAID0 while doubling your possibility of losing all data on the RAID0 array. The potential speed advantage from a RAID array is that you can be transferring data from one HDD unit's buffer to your CPU and RAM while the other unit is still seeking the data it wants from a different place, so you don't have to wait for that second data chunk to be found. But the fact is that disk speeds internally and their large buffers now mean that data are made available so fast that it is waiting in the buffer for the CPU to catch up in many cases. This is especially true when you are dealing with sequential access to a long string of sectors in a large file so that an entire disk track or two can be read into the HDD's on-board buffer (or written) in one disk revolution. That is exactly what happens for your application - reading and writing very large files of video data, with few pauses to find the start of a different file.

For me, I'd put more weight on the costs. The 1.5 TB drives are $110 each, the basic 2.0 TB unit is $200, and the RE version of 2.0 TB with double buffer size is $310. That last one is particularly designed for 24/7 use in a server environment with a very long projected lifetime. So for $220 you could get 3.0 TB or 2.0 TB (slightly less $), and I'd go for the larger two-disk option. Now, you could do that as RAID0 but don't expect any significant speed-up, and be aware of the higher possibility of total data loss. An advantage of RAID0, of course, is that the array appears to the OS as one drive with a capacity of the total for two disks. That may not matter to you - you might be happy just using separate storage devices for groups of work. Or, if you really want one huge storage space, consider the JBOD version of RAID in which two or more HDD units can be grouped as one "drive". But remember, any RAID system also carries with it the potential problems to handle if your RAID controller (maybe the mobo if you are using built-in RAID) fails and must be replaced - poor RAID standardization means it is hard to change controllers and still read old disks.

For $500 I'd look at two options. First, working "without a net", would be to buy four 1.5 TB drives, use them as individuals, and have 6.0 TB of storage. Save the extra $100. But better, especially since you will do video work for sale to clients, is to be sure you have a reliable backup system for your files. Buy four of the 1.5 TB units and mount two in your computer. Then buy this external two-bay case:

http://www.tigerdirect.com/applications/SearchTools/ite...

and mount the other two drives in it. (For twice the price, there is also another model with more interface options and more RAID options, but I don't think you need them.) Although the only interface here is USB2 (others are faster), for use mainly as a backup unit you can tolerate slightly slower performance. Make your backups to this unit periodically (and remember to verify that the backed up data is good and actually CAN be recovered!), then disconnect it entirely from computer and wall power to isolate it. Best, even, is to store it off-site when not in use. Now you have both lots of storage AND a reliable backup system. All that's needed is will power to DO the backups. In fact, with reliable and up-to-date backups, you would be in a much better position to use RAID0 or JBOD in your main computer's pair because you will be prepared to recover from the disaster of disk failure.