I can't wait until the local disk in servers and blades is as quaint a notion as 5.25-inch floppy drives and rumble seats. Make no mistake, it will happen. It's just a matter of time.
Local disk is already passé. You can easily do away with local disk in most situations by booting from a SAN or running the server with an embedded hypervisor such as VMware ESXi. RAM is inexpensive and plentiful, and the very idea of swapping to disk is becoming more and more ridiculous every passing day. At this point in time, there's basically no reason to ever have a server use significant swap space and certainly not for active processes. A server in that state is basically overwhelmed and needs to be upgraded or replaced.
[ Looking to revise your storage strategy? See InfoWorld's iGuide on the Enterprise Data Explosion. ]
In fact, local disk in servers should probably be relegated to remote offices and smaller branches where there is no SAN. Relying on local disk in a data center full of SAN storage is simply redundant, yet you cannot buy a server from a major vendor that has no disk subsystem.
Sure, you can buy servers without physical disks, but there's still a hot-swap cage, a SAS/SATA backplane, disk controllers, cabling, and all the airflow designs present in those servers to account for the possibility that there might be a bunch of hot, power-hungry mechanical hard drives spinning at the front of the box. Dispensing with the notion of local disk altogether completely alters the design of a server from top to bottom: power, cooling, cabling, everything. Such a server would run cooler and require less power than a disk-laden counterpart and would be cheaper to design and manufacture to boot. It's a win all around.
In fact, those concepts carry even more benefits in the blade space. A blade chassis freed from the bonds of any form of local disk would reduce power and cooling requirements exponentially and might even result in higher blade densities per chassis -- again, a win-win scenario.
What I would want in such a server is very simple. There should be an embedded flash drive or a couple flash media slots baked onto the mainboard, nothing else. Give me at least six gigabit NICs or two 10G interfaces, an out-of-band management coprocessor, at least two sockets, and a sea of RAM. I'd like to see at least three 16x PCIExpress slots and a smattering of USB2 ports on the front and back (and one on the inside, natch) and maybe even embed a KVM-over-IP port with a legacy breakout dongle for the tired old SVGA and PS/2 ports. Box it up into a package that would probably be 30 percent shorter than the traditional 1U server.
I can turn that box into just about anything. It's obviously a natural for virtualization, but booting from a SAN can turn it into a powerhouse database or application server. In fact, if you're working from 4Gbps or even 2Gbps Fibre-Channel, your SAN will be faster than local disk could ever be and more reliable. If you have an iSCSI SAN, there are options to boot from that too, and again the disk I/O is likely to be faster.
There are some fixed-purpose blade server options out there that carry no physical disk, but they're parts of larger infrastructure endeavors and aren't available as general-purpose systems. Maybe it's about time for one of the major server vendors to break the seal on this concept and offer a completely diskless design for the masses. We're waiting.