The Cost of Big Servers

I decided to compare the cost/benefit of a blade arrangement versus a "big server" setup. For the comparison I've configured a Dell PowerEdge M600 as my blade and a Sun Fire X4600 M2 as my "big server" setup.
Price:
Dell = $2,605
Sun = $15,995.00

CPU:
Dell = 2xQuad Core Intel® Xeon® E5405, 2x6MB Cache, 2.0GHz, 1333MHz FSB
Sun = 4 Dual-Core AMD Opteron - Model 8222, 3.0 GHz

RAM:
Dell = 8GB 667MHz (8x1GB), Dual Ranked DIMMs
Sun = 16 GB (8 x 2 GB DIMMs)

Disk:
Dell = 2x73GB 10K RPM Serial-Attach SCSI 3Gbps 2.5-in HotPlug Hard Drive
Sun = 292 GB (2 x 146 GB) 10000 rpm SAS Disks

OS:
Dell = RHEL 4.5ES (although I would put some other Linux variant on if it were up to me).
Sun = Solaris 10 (shocker, I know)

Roughly, the Dell is 6x cheaper than the Sun, which means I can buy 6 of them for the price of the Sun (duh). Now, partitioning that system could create two database servers (those would need more disk, obviously) and four application/web servers. So for the price of one "big server," I've already got a cluster of four app servers and a cluster of two database servers. Arrange as needed for your system.

Throwing disk arrays into the mix continues this thought. Comparing a Dell PowerVault NF600 to a Sun StorageTek 5320 NAS Appliance again shows the case against "one big server", even though we're comparing Network disk servers

Price:
Dell = $4,926
Sun = $ 48,164.00

Disk capacity:
Dell = 4x400GB 10K RPM Serial-Attach SCSI
Sun = 16 x 500 GB 7200 rpm SATA Disk Drives

CPU:
Dell = Dual Core Intel® Xeon® 5110, 1.60GHz, 4MB Cache
Sun = 1 x 2.6 GHz (assuming AMD)

Now we're in the ballpark of 10x price difference. So I could have 10 Dell NAS drives serving my 6 servers (again, I know there's no reason to have 10 drives for 6 hypothetical servers, but just to prove a point), vs one big drive serving one big server.

The price of adding "commodity-level" hardware is so (relatively) low, that there's almost no reason not to do it. Planning to build on this type of architecture quickly leads to partitioned applications, so that a new application can get its own host, or any service that needs more power gets more power, rather than improving the performance of the service. Figure $100/hour per developer. If it takes more than half a man/week to profile, re-code, retest and redeploy the service, you'd be better off throwing hardware at the problem. And as the net load on the system grows, it's much easier to build out horizontally when the increment size is small.

Now I know that you can run multiple virtual servers on one "big server", but the point I'm trying to get across is that the bang-for-the-buck of the "little" servers is much much greater, and acutally building around small servers creates a more modular, scalable software architecture.