- Vendors have economies of scale making general-purpose computers.
- Users have economies of scale running homogenous, general-purpose computers.
- Virtualization will work.
But when one thinks a little bit about what’s really driving the use of appliances, those arguments fall apart.
Throughout the history of commercial computing, special purpose data center devices have succeeded in two areas — communications, and high-volume storage — for three main reasons:
- These uses involve moving lots of data, at high speeds. Unnecessary overhead hurts.
- These uses are generally simple and repetitive. Much of the overhead of flexible, general-purpose computing is unnecessary.
- For internet devices only, most especially ones that do security.) Single-purpose devices are much easier to lock down.
Since the mid-1990s, communication/networking has been exploding as a fraction of overall computing — and therefore, the same has been true of appliances.
If you don’t think this trend will continue, then probably either:
- You think Layer 7 inspection will reverse it, because a device that can do Layer 7 inspection needs to be able to run general-purpose apps.
- You think virtualization will reverse it, because virtualization lets hardware be optimized for multiple kinds of uses at once.
But I think both of those opinions would be wildly overstated.
A good illustration of these points may be found in an exchange I had with Stuart Frost, CEO of DATallegro. DATallegro is a data warehouse appliance maker heavily optimized for streaming data on and off disk, moving it between mulitiple processors, and making the best use of onboard cache, memory bus, etc. Stuart thinks it’s likely that he could get much of the same benefit from shipping on a known configuration of name-brand equipment. But I can’t imagine any way that DATallegro’s software would work well on any kind of virtualized multi-purpose grid kind of setup. Blech. The vast majority of their engineering would be simply wasted.
Nor will Cisco routers be replaced by software running on Sun grids any time soon.