> Another trick I've read about is called quarter stroking your disk.
> Apparently you can create a partition on a 7500 RPM disk such that
> the partition is only using the inner portion of the disk, so that
> the arm doesnt move so far. Doing this is apparently faster than
> using a 15k SAS disk, and much cheaper, and plus you still get the
> slow part of the disk to use for storage.
Well it's not as simple ;-) - "quarter stroking" *can* speed up head positioning as long as you don't use the other portions of the disk. But similar concepts are implemented in nearly every file system driver. E.g. the middle of the disk is used to store directory information and the data is arranged around it. Chunks of a file are stored near to each other as long as there's enough space left for an optimal placement. Only if the filesystem is nearly full, the chunks are placed non-optimal.
This is the reason why you never should fill a files system above approx 70%.
Another thing to point out: It's not the inner side of the disk which is the fastest, it's the outer side. The disk surface below the head has an higher speed here, so you can store more data in a given time than on the inner side.
Just in case i didn't already mention: I strongly suggest everyone who is not perfectly sure what he's doing to use a standard setup instead of tweaking the system. There are chances that the system become worse than before...