Ideal configuration for oracle?

Many thanks to all

2.5" Small Form Factor SAS, you can get more of them in the box that way. 36GB and 72GB 15K or 72GB and 147GB 10K. Of course they cost as much or a bit more than the 3.5" flavour but the seek time is generally better.

According to SAME in the above doc all you split are the redo logs from the data, and if you copy the logs from one server to another even that goes on the data spindles. I like wasting disk space, it means you can avoid using the slower inside of the platter.

One more important ratio is the space/transfer.  Two 15K 72GB is going to work out much better on most applications than a 147 10k.  Effectively it's 30k theoretical bandwith on roughly the same storage.  It even makes it easier to use RAID.  But, ultimately, unless you have multiple i/o channels and cards, there is a diminishing return with each device as well as real physical limits on power, mountings, and connections.  Also, the more drives you have the less time (on average) there is between failures.  If you have a MTBF of one year (just an example) and you have 2 drives, then you can expect to have a failure every six months.  But, if you have 52 drives, then you're replacing one every week.

Good luck!

Indeed. When you look at the TPC benchmarks what looks like a fairly cheap server on the face of it has 10 RAID controllers or F/C HBAs and several hundred disks making it rather more expensive. But like it says in the SAME document it doesn't have to be that difficult at least not for normal size systems.