Data security and integrity don't get the same attention as physical infrastructure in a colocation facility. But power and cooling failures at cloud and data center hosting sites take down multiple clients and services.
Before negotiating with data center providers, determine the level of redundancy, uptime and so on required for your IT operations. To ensure that providers meet the criteria, scrutinize and test the contract, and inspect the physical data center facility whenever possible.
Write the right contract
Data center providers write contracts to protect themselves, rather than your company. Consider bringing in a specialist to negotiate all the facets of these legally binding contracts; your corporate lawyer is unlikely to know what makes for a risky data center versus a high-uptime, redundant, secure one.
On the facilities side, there are two major contract terms to scrutinize: the costs of changes and the service level agreement (SLA).
IT is a dynamic business, where changes can quickly negate any cost benefits from contracting with an outsourcing provider. In general, the most cost-effective services in a hosted environment are fairly stable. Ask data center providers: What types of expansions or contractions will you accommodate? What constitutes a change? How will it affect billing?
Hardware and applications that grow, shrink or change on relatively short cycles may be poor candidates for hosted services, or may be better accommodated by one service provider than another. One of the benefits of cloud computing is the ability to react to fluctuating workload demand, but this is quite different from having a high rate of physical equipment churn.
With a stringent SLA, costs for outsourcing services increase. Data centers that are certified to a standard, such as Uptime's tiers or TIA-942 ranks, will provide the documentation from that organization. Most hosting facilities aren't certified, however, and self-certification isn't worth much. If the data center is not third-party certified, closely examine what the provider is willing to offer in the SLA.
You can test the provider's legitimacy by negotiating on the SLA. Ask for a higher level of availability than you really need. A data center provider rated Tier II by The Uptime Institute shouldn't be willing to contract for Tier IV availability, at any price. The cost differential between Tier III and Tier IV reliability, or the level of compensation offered in the event of a failure, also indicate how confident the provider is in its space and operations.
If you can do a physical inspection of the site, walk through with a professional experienced with high availability and fault-tolerant design and operation. This is not as thorough as a full certification review by third parties like Uptime or TIA, but provides answers on physical security, power and cooling scalability and redundancy, energy efficiency and connectivity.
Outsiders, or other tenants and customers, should never have access to your hardware and systems.
Keep your cool
Power and cooling scalability is primarily a concern if your IT organization plans to house owned hardware at colocation sites.
What range of power and cooling can be provided to the equipment area? How easily is it scaled up and down? Scaling costs should be fixed in your contract.
Today's data center cabinets easily average 5 kW to 10 kW each, but if you anticipate using some higher-density cabinets, find out if and how the provider accommodates them. If high density is handled via local systems, such as in-row cooling units, will the floor space for the air conditioners be taken from your rentable area, or will there be a cost offset for this area used for facility infrastructure?
The power to back you up
Effective redundancy is much more than just having extra air conditioners or uninterruptible power system modules -- how they interconnect and operate is just as critical.
To ensure power and cooling redundancy at a data center provider, examine design and construction documents, physically observe the facility and review the language in the SLA. If the facility is certified to an Uptime or TIA level, you can skip this investigation.
Save your energy
Energy efficiency should be important to everyone, especially if the outsourcing partner charges for actual, metered power use. Power can easily be your highest expense.
If a data center provider's base cost is lower than its competitors', make sure savings won't be offset by higher energy bills. Highly efficient designs are more expensive to build, which can mean pricier leases, but the investment can be quickly offset in energy savings.
Include a guaranteed power usage effectiveness (PUE) number in your SLA at typical levels of operation: 25%, 50%, 75% and 100% of contracted long-term power requirement. The SLA should include power cost offsets if the guaranteed PUE is exceeded, as well as a description of how PUE is calculated and tracked. Your services must be separately metered within the facility to capitalize on this type of SLA.
No service, be it cloud, hosted servers or colocation space, is of any value without outside connectivity. Examine the facility's network service providers' uptime histories, routing from central offices into the building, and guaranteed traffic levels. If a single street cut or storm damage could interrupt all connectivity, then it doesn't matter how many providers feed into the site.
About the author:
Robert McFarlane is a principal in charge of data center design at Shen Milsom and Wilke LLC, with more than 35 years of experience. An expert in data center power and cooling, he helped pioneer building cable design and is a corresponding member of ASHRAE TC9.9. McFarlane also teaches at Marist College's Institute for Data Center Professionals.
These questions will tell you a lot about the physical characteristics of the hosting service, but there are many more factors to consider when comparing data center providers.
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