Cost comparison: Public Cloud vs On Premises

AWS:
http://aws.amazon.com/ec2/pricing/
http://calculator.s3.amazonaws.com/index.html
Azure:
http://azure.microsoft.com/en-us/pricing/details/virtual-machines/#Linux
vCloud Air:
http://vcloud.vmware.com/service-offering/pricing-calculator/on-demand
Google CGE:
https://cloud.google.com/compute/pricing
https://cloud.google.com/products/calculator/

Following is a comparison of Public Cloud to traditional On Premises infrastructure. All prices in AU$.

Compute:

	Cost 3 years (AU$)	Cost/VM (VM = 2 vCPU, 8GB) 3 years (AU$)
Public Cloud - On demand:
AWS on demand m3.large (US$0.196/hr)		$4,854.32
Azure on demand D2 VM (AU$0.2412/hr + GST)		$7,106.33
vCloud Air on demand ($0.017/Vcpu/hr, $0.026/GB/hr)		$8,368.11
Google GCE in US on demand n1-standard-2 (US$$0.126/hr) - Estimate Aust cost 30% higher		$5,772.66
Public Cloud - Lowest cost 3 year option:
AWS 3 yr reserved instance m3.large		$1,806.58
Azure on demand D2 VM (AU$0.2412/hr + GST)		$7,106.33
vCloud Air  on demand ($0.017/Vcpu/hr, $0.026/GB/hr)		$8,368.11
Google GCE in US sustained use n1-standard-2 (US$$0.088/hr) - Estimate Aust cost 30% higher		$4,031.70
On Premises - 3 year cost:
On Premise DL380 G9: 24 cores, 384GB - can support 48 VMs each 2vCPU/8GB	$15,000.00	$312.50
as above plus facilities - rack+power at Equinix $2,500/month - say 1/10 rack	$24,000.00	$500.00
as above plus VMware license - vSphere Ent $5125/CPU + $1282/year support	$38,096.00	$793.67
as above plus staff to manage  - resource cost = $150,000/year and can manage 20 vSphere servers	$60,596.00	$1,262.42

Storage:

Currently most on Premises infrastructure is:

• Underutilised, not running high level of utilisation as shown above, hence
• higher server hosts
• higher Virtualisation costs
• higher backup costs
• higher data centre facilities costs
• High level of expensive bloatware that is not necessary
• Expensive storage that is double or triple of above costs
• Expensive backup costs
• Expensive networking costs

On Premises infrastructure lacks the features found in Public Cloud::

• Pay as you use, no capital upfront - OPEX rather than CAPEX
• Elasticity
• Software defined data centre, everything is an API. Easy for automation
• Many services (Database, Email, VDI, Low cost object storage, Payments, Messaging, Notification, Workflow, Transcoding, Data Warehouse, Big data, etc, etc)
• Save costs by stopping instances at night/weekends/holidays
• Future reduction in  pricing as cloud prices continue to drop
• Enterprise apps market place (Just select application in best of breed installation)
• No need to purchase software: virtualisation, operating system, database, middle ware, monitoring, backup, system management
• No long term commitments
• Easy to scale
• Easy to move to new geographies
• Single support contact

Update 21/8/2015: Many other sites recognise that if you need servers 24 x 7 it is lower cost with dedicated servers:
http://deepvalue.net/ec2-is-380-more-expensive-than-internal-cluster/
https://gigaom.com/2013/10/10/amazon-web-services-should-you-stay-or-should-you-go/