Service Provider Uptime- Colocation

As described by Wikipedia, uptime is a measure of the time a computer system has been "up" and running.  While that definition describes uptime specifically for a computer, uptime measurements are the single most important measurement for colocation and managed hosting providers today.  Its the basis of the SLA they provide, but it's also the standard of performance every provider strives for.

Before we discuss the definition of uptime for service providers, its worth our time to discuss the meaning as it relates to the services the provider is going to give you. 

When asked about up-time, every service provider thinks about it in a different way.  Some will say that downtime is defined as an unexpected event that renders a particular service out-of-service for a prolonged period of time.  Additionally, every SLA for up-time- even when its 100% guaranteed, will include provisions for planned downtime.  So, its wise to understand how those up-times and planned outages are defined in your contract.  If the provider doesn't provide their service using N+1 redundancy, there's a strong likelihood that you will experience downtime because of routine maintenance.  Normally, if this occurs, you're most likely dealing with a Tier2 provider.

So, how is up-time measured for service providers?  That question is somewhat ambiguous because, in some ways, its a philosophical argument.  However, there are guidelines that provide some ideas on how service providers measure themselves:

It goes without saying that in some cases, a great deal of planning and investment is required for a service provider to be able to live up to these standards.  The amount of manpower and capital needed to achieve near 100% up-time is significant.  At the end of the day, relying on a service provider to meet or exceed these up-time guarantees is simply what is expected, so finding a provider with strong financial's and a solid track record is paramount.  If you understand how the provider deals with downtime (planned and unplanned), you're arming yourself for a good contract negotiation.

Reliability is the name of the game, customers rely on the colocation or managed hosting provider to deliver a service that is as good or better than what they could do on their own.  The components that are measured by their uptime are pretty straight forward.

Colocation providers focus on several things:

• Power:  Definitely the single most important element for a colocation provider.  They achieve HA (high availability) by investing money in multiple power feeds from the utility provider, redundant ATS (automatic transfer switches), multiple generators and UPS systems. 
  
  In addition to these redundancies, you will also hear providers discuss A&B power feeds.  By doing so, most providers will achieve true A & B power by providing you power drops from different distribution sources.  In some data centers, the use of the Starline Buss system gives them the ability to easily provide multiple power drops from multiple sources.  But beware, if it looks like it's coming from 2 separate sources, make sure that you understand how the power is sourced.  Meaning, its only true A&B power if the "B" side power is sourced from a different set of UPS systems and distribution.
  
  
• Cooling:  This is the second most important element in the colocation center.  Most, if not all Tier 3 data centers will have more than one cooling unit (AHU or CRAC) to achieve N+1 redundancy.  Be sure you also understand if the cooling source is redundant and that it is power runs through the main UPS and generator systems.  If there aren't multiple cooling loops, there is effectively a single point of failure in the cooling systems design.
  
  
• Network:  Any data center worth looking at is outfitted with multiple internet providers connections.  As long as there is more than 1, you're dealing with a Tier 3 data center.  You'll find that some data centers provide more than 2 and that's a good thing.  However, it's worth exploring how the routing is handled and if they are using any special BGP routing to ensure that your outbound traffic is sent across the best route, not the cheapest.  In addition, a multi-homed network and redundant distribution is a must.  Be sure to always ask for multiple network drops if you're buying your internet connectivity from the provider.

Overall, colocation is going to continue to play a significant role in the IT budgets of the future.  More companies are strategically shedding items out of the budget that are not in the core competency.  I remember discussing this with the CIO of company here in Denver.  He put it quite frankly when he said managing generators, ups systems and network have nothing to do with the existence of the company.  What made them great was making their product, not managing the uptime of a generator.


(Hosting Providers uptime will be covered in another article.)