Blade server adoption has been discussed for a number of years now, but the form factor hasn't been embraced in the way it was initially expected. One of the main reasons is that they are often referred to as "hot little power-suckers." That can't inspire confidence in the data center managers now dealing with the near ubiquitous concerns of power, space, and cooling.
For most, the tried and trusted 1U and 2U rack mounted servers have been reliable and familiar workhorses, dramatically reducing the urgency of blade adoption.
But power is far from the only sticking point hindering blade server success.
In the configuration puzzle to cram CPU resources into a blade, and still keep them from delivering roasting-level temperatures, other items had to go....most notably disk drives (hey that is what network storage is all about right?) and also the amount of memory per blade. Unfortunately, you simply can't have all of your CPU, disk, and memory resources in a much denser form factor without shaving a little bit here and there.
The difficulty is that when you remove disks and memory from the equation, that means the CPUs are spending more time traversing a network to get their data. Removing the disks alone are a big item, as what may have been temporary stored on local disk is now gone, but further reducing the amount of RAM per blade means that the applications need to go out to disk more frequently than before.
This double-whammy of reduced memory and I/O capability within a single blade puts extra pressure on the network storage infrastructure within blade-centric data centers and often leads to I/O bottlenecks that can severely impact application performance.
Just as servers have changed their form factors, caches are in the midst of a similar transition. Once hidden within single servers or storage systems, caches can now be deployed as a shared network resource.
Scalable caching appliance such as CACHEfx from Gear6 enable customers deploying blades to externalize caching on the network and serve data instantly to I/O intensive applications. The end result is better blade utilization, and freedom to adopt blades regardless of disk-less or light-memory configurations. Scalable caching appliances can serve data from any number of storage systems to any number of clients. They can also expand on the fly to meet increasing application workloads.
Most of the blade server vendors are refining and reducing power footprints. That, combined with the availability of instant accessible I/O might cause data center managers to bring blades back from the future and closer in line with current planning.
The whole premise The author of this article obviously isn't familiar with HP's C-Class blades. "Hot little power suckers" isn't the title I would give to a blade system that can save you 20-30% of the power and heat footprint of an equivilent 1U rack mount system.
HP also disproves the "other items had to go....most notably disk drives" theory. You can easily connect 2 - 10 hot plug disks to a blade in a C-Class enclosure. That will give a blade up to 1.4TB of local raw disk. I wouldn't call that storage constrained. But blades are targeted at applications that are already SAN connected, or don't need much disk.
Posted by: Blade Guy | October 09, 2007 at 04:27 AM