In this model, you own the equipment but the physical environment it sits in is owned and operated by the service provider. You dont have staff of hardware engineers and you dont have a computer room to manage or pay for. The advantage is you will be more likely to have a robust physical facility with multiple sources of communication and power. That will help ensure that your systems are available in the event of a disaster. The downside is that you wont have quick, physical access to the machines.
Youre also paying for the physical plant so it will be more costly that having the machines on-site. However the odds are you wont have the same level of physical security and reliability on-site so you have to weigh that risk against the cost of a better environment. Youll still have the cost of owning and maintaining the equipment. Youll also have to pay, as in the in-house model, for expertise to manage your systems.
A place to put your equipment (rack space);
Connectivity from your office to the data center;
Connectivity from the data center to the Internet; and
Reliable power and communications infrastructure.
Each of these items has numerous options that youll have to sort through to get the appropriate configuration.
Racks - Rack space is measured in 1.75 in high Rack Units (RU or U). The height of your equipment determines the amount of rack space youll need. A typical rack will hold 40U, so if you have 6 servers each 2U high, then youll probably need at least a third of a rack.
Connectivity - Connectivity to your network and to the Internet is whats needed to make sure that you can communicate with your servers. These connections will come in a variety of bandwidths ranging from the equivalent of DSL speeds up to the highest speeds available. You will have to decide what amount of data you are going to move between your office and the servers to determine how much bandwidth you need to pay for. If you have heavy traffic to a server based application then youll want to have more data bandwidth available on that side of the equation. The same is true of the Internet connection: if you have a lot of data coming in from the Internet (such as an ecommerce application), then youll want more bandwidth to accommodate that.
If youre just doing normal office Internet surfing youll probably need less Internet bandwidth. You should purchase the amount of bandwidth that you use on an average basis. There will be a surcharge for using more than that, but that can be mitigated by making sure that the surcharge is based on a 95% measurement of sustained usage. If you push a lot of data to your servers occasionally, that wont cost anything extra.
Power - The power in the data center should be backed up by an uninterruptible power supply (UPS) to ensure that in the event of a power outage, the equipment will continue to run long enough to enable a clean shutdown. Additionally, youll want to make sure that the data center has a generator available to provide power in the event of an extended power outage.
You should also check on the fuel resupply contract that the data center operator has for their generator(s). Youll want a fuel resupply contract that ensures the generator will continue to operate over several days just in case the "ice storm of the century" takes out the power lines.
Communications - Communications between your office and the data center are crucial to a successful outsourcing project. You will want to make sure that the data center has multiple carriers supplying communications. The data center should have very large bandwidth data lines coming in from those carriers, again to make sure that you dont have a bottleneck communicating with your servers.