The use of Amazon’s dedicated cloud instances may be on rise, but does that make sense?

AWS Summit

Dedicated cloud instances are something of an oxymoron. The traditional understanding of cloud computing is that it runs stuff from many users on shared infrastructure. Dedicated instances, by definition, aren’t shared and thus could appeal to a class of users who worry about the drag that neighboring workloads can have on their jobs — the so-called “noisy neighbor” problem. They also may suit those who see shared infrastructure as not compliant to various industry regulations.

There are enough companies worried about such things that Amazon Web Services launched dedicated instances in March 2011 and significantly cut prices on them in July. Since that price cut — which amounted to nearly 80 percent in some cases — the use of AWS dedicated instances has risen significantly, according to Cloudyn, which monitors AWS and Google cloud usage for customers.

In a blog post, Cloudyn VP of marketing Eron Ambramson wrote that before July 2013, dedicated instances were hardly used at all. But now, 9 months after price cuts, 0.5 percent of the instances it monitors are dedicated. (Cloudyn said it has eyes on 8 percent of total AWS workloads.)

Percentage of workloads running on AWS dedicated instances by region.

Regional breakdown of Cloudyn’s AWS customers.

The price differential now between dedicated and regular on-demand instances is about 10 percent, although dedicated instances also incur additional run-time charge of $2 per hour per region — which for big companies is “outweighed by the advantages and peace of mind of having your own dedicated hardware,” Abramson wrote.

Server Density CEO David Mytton said AWS needs to offer dedicated resources since rivals offer very fast bare-metal capabilities, which he argues can also be cheaper than shared cloud infrastructure in some use cases, a topic that Mytton and others will address at Structure in June.

“Everyone knows the noisy neighbor problem and AWS doesn’t have a great historical reputation for performance on that front. It’s one reason why Softlayer has an advantage with their fast deployment of bare metal that works alongside their cloud, so you can easily move workloads around,” he said via email. SoftLayer, bought by IBM last year, is now the core of IBM’s cloud computing story.

Dedicated instances? meh.

Others don’t see dedicated instances as a real advantage.

For one thing, performance drag comes more from virtualization itself rather than noisy neighbors, said Joe Emison, CTO of BuildFax, an avid cloud user. “And, noisy neighbors do more damage with respect to network traffic than anything else.” If that is the case, Amazon’s IOPS-optimized Elastic Block Store and scaling options in S3 storage and CloudFront content delivery network address those issues.

“Buying dedicated for performance is a bit like buying premium gasoline to make your Honda Accord perform better — it probably does but shouldn’t you be doing something different if you want to see significant results?” Emison said.

He also discounted the compliance argument. It’s true that some auditors don’t sign off on the use of multi-tenant environments, but those auditors will also “not be OK with other things AWS does even with dedicated instances,” he said. For example, many companies want to be able to tour data center facilities, something that Amazon does not allow, although it does provide a list of third-party certifications and how they are attained.

This story was updated at 8:27 a.m. April 23 to reflect that Amazon does document security certifications for its data center sites.



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