Form Factor.. Is it really Difficult ?

Many a times its difficult to decide on form factor of servers, Folks working on DC Migration/Build/Consolidation projects would generally ask you , "What Kind of server i should suggest to customer" , Well it depends on Multiple factors.. and not very easy to proposition correct Made/Model/Density as per business requirements. People end up with High Density Blade centers where Rack server would have met the requirement and vice-versa. Following are some of the tips which can help you decide whether i should propose Blades or Rack Servers.

Propose Rack Servers When :-

•  Branch Office and Small Data Rooms -Because Blade Center will take 8 to 10 Units depending on Make/Model with Power requirement from 3.5 KVA to 5 KVA with High Cooling requirements and you may not have such infrastructure at remote sites.

•  Large DAS (Direct Attached Storage) Required - Generally Blade Servers are built on High Density Architecture and may not have more than 4 Slots for HDD. 

•  More than 4 CPU Socket required - Majority of Blades would come with 2 or 4 sockets depending on Half/Full Height , You may have a workload which requires more than 4 sockets to operate.

• 4. Serial/USB/ Port Needed for Dongle connection or extenal device connection - Important factor to consider when you have App License on serial Device or USB device.

Propose Blade Servers When :-

•  Space and facility Consolidation - Major driving factor to save cost on Power/Space/Colling

•  Unified Management :- Generally Blade centers comes with Unified Management Modules to provide centralized Management , Although you can buy third party unified management solution for Rack servers but that's the additional investment.

•  TCO on Power & Cooling - Modern Blade centers are equipped with technology which reduces power and cooling requirements. sometimes if you compare the Hosting cost of the server with actual price of the server itself , Hosting cost will be high. Talk to SunGard or Global Logic or other DC hosting providers :) 

•  Cabling Reduction Requirement :- This is another important driving factor. Typically you will have 5 Cables running out of rack servers (1 for iLO/dRack , 2 for Production Network , 2 FC cables for SAN connectivity if SAN storage is required), Number of LAN cable may increase depending on traffic separation and other factor. Blade Servers IO is typically  consolidated and it uses High density BackPlane inside the chassis to communicate with edge switches. HP c7000 can provide 40GB LAN & 32GB SAN connectivity with merely 8 Cables to 16 Half height blades or 8 Full height, Cisco UCS further reduces the cable requirements by 50% as compare to HP (If you are using pass-throughs then no benefits on cabling sure :)) . Having said that if you don't want your data center to look at a "Forest" then cable reduction is important.Look at the picture below if you don't trust me

•  Stateless Server Requirement  :- Lets first Understand what is "State" , it means Identity of the servers Hardware which includes (UID, MAC Address & WWPN Number if it has HBA) - This state is used to define server access to network Layer and storage layer. Now think of a scenario where server Hardware dies and you got Brand new box.  well.. you as server admin have to provide new state of the server  to Network & Storage folks so that that can make changes at their end  access to Storage & Network can be restored. This all requires time (typically 4 to 6 Hrs - this does not include hardware landing/Racking Stacking in DC). Business can't afford 4-6 Hrs of downtime for Mission Critical workload therefore they need some solution to abstract this so called state from the hardware..... well and answer is you got it :) correct!! if not contact me.

•  Fast and Dymanic provisioning - Last but not the least, today we are talking about end to end provisioning of servers in 5 Minutes to 1 Hrs. Its not Possible until you have Mobility & Hardware abstraction. Blade centers are capable of doing all this.

I hope this post was informative, and may help you to some degree.

Next Post :- I am going to write about different  Hardware offerings from HP/Dell/IBM/Cisco...