Frequently Asked Questions
Below is information relating to some of the common ways in which a managed services are required. Click on one of the links below to jump to that section.
What is a private cloud?
A private cloud attempts to mimic the delivery models of public cloud vendors but does so entirely within the firewall for the benefit of an enterprise’s users. A private cloud would be highly virtualized, stringing together mass quantities of IT infrastructure into one or a few easily managed logical resource pools.
Like public clouds, delivery of private cloud services would typically be done through a Web interface with self-service and chargeback attributes. “Private clouds give you many of the benefits of cloud computing, but it’s privately owned and managed, the access may be limited to your own enterprise or a section of your value chain,” Kloeckner says. “It does drive efficiency, it does force standardization and best practices.”
The largest enterprises are interested in private clouds because public clouds are not yet scalable and reliable enough to justify transferring all of their IT resources to cloud vendors, Carr says.
What is a public cloud?
Naturally, a public cloud is a service that anyone can tap into with a network connection and a credit card. “Public clouds are shared infrastructures with pay-as-you-go economics,” explains Forrester analyst James Staten in an April report. “Public clouds are easily accessible, multitenant virtualized infrastructures that are managed via a self-service portal.”
How do vendors charge for these services?
SaaS vendors have long boasted of selling software on a pay-as-you-go, as-needed basis, preventing the kind of lock-in inherent in long-term licensing deals for on-premises software. Cloud infrastructure providers like Amazon are doing the same. For example, Amazon’s Elastic Compute Cloud charges for per-hour usage of virtualized server capacity. A small Linux server costs 10 cents an hour.
Storage clouds are priced similarly. Cloud storage has prices starting at 2.5 cents per gigabyte of storage each month, with additional charges for download.
What types of applications can run in the cloud?
Technically, you can put any application in the cloud. But that doesn’t mean it’s a good idea. More importantly, regulatory and compliance concerns prevent enterprises from putting certain applications in the cloud, particularly those involving sensitive customer data. If vendor offers you to choose a Geo location or Region for your server then you can put any application on Cloud.
IDC surveys show the top uses of the cloud as being IT management, collaboration, personal and business applications, application development and deployment, and server and storage capacity.
Can applications move from one cloud to another?
Yes, but that doesn’t mean it will be easy. Services have popped up to move applications from one cloud platform to another (such as from Amazon to GoGrid) and from internal data centers to the cloud. But going forward, cloud vendors will have to adopt standards-based technologies in order to ensure true interoperability, according to several industry groups. The recently released “Open Cloud Manifesto” supports interoperability of data and applications, while the Open Cloud Consortium is promoting open frameworks that will let clouds operated by different entities work seamlessly together. The goal is to move applications from one cloud to another without having to rewrite them.
What types of service-level agreements are cloud vendors providing?
Cloud vendors typically guarantee at least 99% uptime, but the ways in which that is calculated and enforced differ significantly. Amazon EC2 promises to make “commercially reasonable efforts” to ensure 99.95% uptime. But uptime is calculated on a yearly basis, so if Amazon falls below that percentage for just a week or a month, there’s no penalty or service credit.
How can I make sure that my applications run with the same level of performance if I go with a cloud vendor?
Before choosing a cloud vendor, do your due diligence by examining the SLA to understand what it guarantees and what it doesn’t, and scour through any publicly accessible availability data. Amazon, for example, maintains a “Service Health Dashboard” that shows current and historical uptime status of its various services.
There will always be some network latency with a cloud service, possibly making it slower than an application that runs in your local data center. But a new crop of third-party vendors are building services on top of the cloud to make sure applications can scale and perform well, such as RightScale.
By and large, the performance hit related to latency “is pretty negligible these days,” RightScale CTO Thorsten von Eicken. The largest enterprises are distributed throughout the country or world, he notes, so many users will experience a latency-caused performance hit whether an application is running in the cloud or in the corporate data center.