If you need a highly available colocation facility or infrastructure, platform or software as a service, consider...
data centers that meet Tier III requirements.
A Tier III data center facility, as ranked by the Uptime Institute, is engineered to have no more than 1.6 hours of unplanned downtime per annum. That's a big jump in availability from the lower tiers -- 28.8 hours for Tier I or 22 hours for Tier II -- which makes Tier III desirable for new facilities.
In a Tier III data center, planned maintenance can occur while workloads are on-line due to equipment redundancy in core areas. Failure of a single item will not cause the area to fail completely. Tier IV takes redundancy one step further, but is only required when you need maximum availability of the facility and IT platform. For most enterprise IT requirements, Tier III is sufficient.
Lots of colocation, hosting and cloud vendors indicate that they are in the range of Tier III (or more often, "Tier 3") -- many of which are not fully compliant with all of the Uptime Tier guidelines. It's a buyer-beware market, so take these steps to ensure that what you are getting is fit for purpose.
Certifiably high ranking
The easiest way to choose a true Uptime Institute Tier III data center is to only look at certified providers. Each of the three Uptime Institute certification types requires a facility to partner with the Uptime Institute Professional Services company and undergo an audit on plans, operational approach or the physical data center.
Auditing the plans results in a Tier Certification of Design Documents. Uptime gives facility owners a certificate and they can be listed on the organization's website.
Physical data center certification is obtainable after the data center plans are certified. Uptime Institute Professional Services carries out a site visit and a full audit of the physical facility to ensure that the build is in line with the plans. If this is the case, then the facility owner receives a Tier Certificate of Constructed Facility with a plaque and a listing on the Uptime website.
The Operational Sustainability Certification involves an on-site visit to evaluate the effectiveness of management, operations and building characteristics. These are evaluated based on the specific requirements outlined in the Institute's document "Tier Standard: Operational Sustainability." Once validated, the facility owner gets a certificate, plaque and listing on the Institute's site.
When looking for a verified Tier III facility, start at the Uptime Institute's website -- all certificate owners are listed there.
We'll have our own party
Should non-Uptime certified facilities be avoided? Not at all. Some believe that the Uptime Institute is too self-centered and that its certification process is not open enough. Some data center facility owners object to paying for the certification process. Others do not see the point of having an Uptime Institute tier system at all.
The Telecoms Industry Association (TIA) came up with a similar four levels of facility tiering (Tiers 1-4) in 2005, under document ANSI/TIA-942. These requirements have been modified every few years to reflect changes and advancements in data center design. In 2014, TIA agreed to stop using the term "Tier" in its documents. However, TIA rankings roughly equate with the Uptime Institute's tiers, and as such, any IT team looking for Tier III data center space can evaluate facilities that meet what TIA defined as Tier 3.
For those facilities that do not have an Uptime Institute Tier III or TIA 3 ranking, it's your job to carry out due diligence. Read through the Uptime Institute or TIA documents, pull out the areas that you believe to be of the most concern and insist that a prospective facility owner shows how they meet them.
Don't accept responses like "Of course -- but we do it differently." Challenge the facility operator; get them to quantify risks and show how they will ensure defined availability targets; get them to couple financial or other penalty clauses with a service-level agreement so that they are invested in managing availability successfully.
When you carry out your own site visit, ask questions: Where's the second generator? What happens if that item fails? How do multiple power distribution systems come in and distribute around the facility?
It could prove costly to sign on with a facility after taking its assurances at face value. Many facility owners will promise almost anything to get higher levels of occupancy. Once you are in the facility, it is difficult to move out again.
Certainly, the Uptime Institute's certification is the gold standard as it is based against a rigorous evaluation of plans, facility and operational processes with solid requirements. The TIA is an open approach that puts more of the weight of due diligence on the buyer. A facility "built to Tier III standards" requires more investigation and thorough understanding of your own requirements.
No matter which route you take for facility selection, remember that these tiers only apply to the facility itself, not how the IT equipment is put together. You can only expect high availability if the infrastructure is equally sound.