On Fri, 23 Jan 2009, M. Edward (Ed) Borasky wrote:
> * large-capacity inexpensive rotating disks,
> * a hardware RAID controller containing a battery-backed cache,
> * as much RAM as one can afford and the chassis will hold, and
> * enough cores to keep the workload from becoming processor-bound
>
> are good enough. And given that, a moderate amount of software tweaking
> and balancing will get you close to a local optimum.
That's certainly the case for very large-scale (in terms of data quantity)
databases. However, these solid state devices do have quite an advantage
when what you want to scale is the performance, rather than the data
quantity.
The thing is, it isn't just a matter of storage heirarchy. There's the
volatility matter there as well. What you have in these SSDs is a device
which is non-volatile, like a disc, but fast, like RAM.
Matthew
--
Anyone who goes to a psychiatrist ought to have his head examined.