Posted By Industry Perspectives On March 31, 2011 @ 8:30 am In Industry Perspectives | 4 Comments
Shirin Elkoshairi of ColoAdvisor  is a Principal Consultant, who works with clients in making informed decisions related to cloud, colocation and managed hosting.
There are a many factors to consider when selecting a cloud computing provider. The good news is that many cloud providers don’t have long term agreements to lock you in one place for a considerable time. In any case, it makes sense to carefully evaluate any provider before signing an agreement, because moving from one provider to another can be a bit of a hassle.
In addition to ensuring that your OS and other processor specific needs are supported, makes sure you review these other items that can be easily overlooked:
1. All the items that you will be “self managing” should be run by your cloud provider. If a simple task requires you to open a trouble ticket, this could be a sign of a missing feature or an immature product, so calculate the risk of wait times for support staff response.
2. If you are working on a disaster recovery scenario, chances are that your existing virtual server instances can’t be just sent to the cloud provider “as is” for use. You may have to build the image from scratch and migrate your data afterward. This is typically the case, as providers need to maintain a special OS build with specific IP addresses for backup and monitoring data that will connect to your OS instance.
3. If you require a database, ensure that the provider will be able to provide enough disk I/O to support your needs. Double check their ability to connect you to a traditional dedicated server, in case you need the processing power to keep up with the application. If you run a clustered database of any type, definitely review this with your provider at length before committing, as many cannot provide a database cluster in the cloud. This is mainly due to the additional VLANs required between the 2 database servers for heartbeat monitoring as well as general I/O issues.
Some Cloud providers are geared towards the provision of “full time” applications that will run perpetually in their environment. These tend to be server instances billed daily that can be turned on and off at will. Auto expansion and contraction (of computing resources) may not be part of the service. Other providers price the use of their environment at competitive rates for short term use or bursts, but then don’t seem to be priced competitively for perpetually needed applications. Determine your needs carefully – whether the cloud will be somewhere to which you can send excess load or if you are putting the responsibility of certain applications entirely outside your own data center.
Look for a provider that has an easy-to-understand pricing model and examine where the monthly costs can be easily predicted. Many will provide the ability to assign cost codes to internally bill departments within your firm. Ideally your billing will be done per cloud instance per day or even hourly if available.
It’s a good idea to have a thorough understanding of the scope of services being purchased. Many times the cloud is an infrastructure management-only service. If you are looking for management of the OS and application, this may not be available at all or will come at an additional cost.
Another element to investigate is the timing of instances. You probably want them provided quickly (less than 1 hour) and in an automated fashion. This is certainly in your interest because you can never tell when a project needs an additional server or if late-night testing of an app is required.
Also, you should avoid signing long-term agreements unless there is a large cost savings. This allows you flexibility. Since cloud services use pooled resources, the provider cannot claim to have invested significantly in your specific deployment unless you have dedicated equipment allocated to you.
Industry Perspectives is a content channel at Data Center Knowledge highlighting thought leadership in the data center arena. See our guidelines and submission process  for information on participating. View previously published Industry Perspectives in our Knowledge Library .
Article printed from Data Center Knowledge: http://www.datacenterknowledge.com
URL to article: http://www.datacenterknowledge.com/archives/2011/03/31/tips-for-purchasing-cloud-computing-services/
URLs in this post:
 ColoAdvisor: http://www.coloadvisor.com/
 guidelines and submission process: http://www.datacenterknowledge.com/industry-perspectives-thought-leadership/
 Knowledge Library: http://www.datacenterknowledge.com/previously-published-industry-perspectives/
 Industry Perspectives: http://www.datacenterknowledge.com/archives/author/industryp/
Copyright © 2012 Data Center Knowledge. All rights reserved.