Feature

Amazon (S3 & CloudFront)

Rackspace (Mosso Cloud Files)

Voxel (VoxCAST &

Silverlining)

Nirvanix (CloudNAS)

Microsoft (Windows Azure & ECN)

Akamai (Cloud Optimizer)

Storage & content delivery

S3 Storage services; CloudFront content delivery

Mosso storage services; content delivery via Limelight Networks

Silverlining cloud services; VoxCAST CDN

Storage services; content delivery via CDNetworks

Azure storage services; content delivery via Limelight Networks

NetStorage services; EdgePlatform content delivery

Service type

On-demand storage in multiple datacenters; on-demand content delivery

On-premises storage

Managed hosting; On-demand content delivery

Managed  cloud storage services

On-demand managed hosting in datacenters

On-demand storage and content delivery

Performance

Comparable latency with customer-owned data centers. Sparsely reported performance problem due to outages

Twice more latency than S3 & CloudFront. Reported stability and performance issues for increased traffic

Reported consistent performance  on par with competitors such as Akamai and Limelight

Storage functions 222% faster and 2 MB sample file transfer is nearly 300% faster than Amazon S3

N/A (System under community technology review. Commercially not yet available)

Up to 400% improvement and at least twice faster application response time than Amazon EC2

Availability & reliability

Availability zones to enable resiliency in case of single location failure, and redundancy

Subject to single point of failure

All time availability as it fails safe against origin server outages

Customizable availability against unplanned outages and redundancy

N/A

No single point of failure, automatic failover and redundancy

Geographic distribution

Datacenters at 14 edge locations in three continents (Asia, North America & Europe)

Partnership with Limelight Networks for coverage at 60 locations

Point of Presence (POP) at 17 locations in Asia, North America & Europe 

Storage nodes at 5 locations in  North America, Europe & Asia

Datacenters at 21 locations. Additional 16 to be added by March 2010

48000 servers in 1000 networks world-wide

Multi-tenancy

Yes

Yes

Yes (also optionally customizable with dedicated servers)

Yes

Yes

Yes

Load balancing

Listed in future investments

Apache as load balancer

Yes (Server switching)

Yes (Global and dynamic)

Yes (Built-in hardware)

Yes (Global and dynamic)

On-demand scalability

Yes

No

Yes

Yes

Yes

Yes

Accessibility

Amazon Web Services API or management console

Browser-based control panel or programmatic API

VoxCAST Web-based portal

Web-based Nirvanix management portal

Azure Services Management Tools

Akamai EdgeControl

Automatic replication

S3: No; CloudFront: Yes

Yes

Yes

Yes

No

Yes

Service Level Agreement (SLA)

99-99.9 %

99.9 %

100 %

99.9 %

99.95 %

100 %

Developer API

Yes (Amazon Web services)

Yes (Cloud Servers API)

Yes (Hosting API)

Yes (Web services API)

Yes (Azure SDK API)

Yes (EdgeScape API)

Economic model & pricing

Pay-as-you-go

Pay-as-you-go

Progressive universal scale billing upon usage

Pay-as-you-go

Consumption-based pricing model

Volume-based pricing; pay-par-use model for NetStorage

Security

Protection for DDoS attacks, access control list and firewalls

Data protection, DDoS migration services, firewalls

Secure authentication, firewalls

Secure authentication, transmission via SSL

Intrusion prevention, .net security, firewalls

Protection for DDoS attacks and application firewall