The biggest problem the cloud solves is hardware supply chain management. To realize the full benefits of doing your own build at any kind of non-trivial scale you will need to become an expert in designing, sourcing, and assembling your hardware. Getting hardware delivered when and where you need it is not entirely trivial -- components are delayed, bigger customers are given priority allocation, etc. The technical parts are relatively straightforward; managing hardware vendors, logistics, and delivery dates on an ongoing basis is a giant time suck. When you use the cloud, you are outsourcing this part of the work.
If you do this well and correctly then yes, you will reduce costs several-fold. But most people that build their own data infrastructure do a half-ass job of it because they (understandably) don't want to be bothered with any of these details and much of the nominal cost savings evaporate.
Very few companies do security as well as the major cloud vendors. This isn't even arguable.
On the other hand, you will need roughly the same number of people for operations support whether it is private data infrastructure or the cloud, there is little or no savings to be had here. The fixed operations people overhead scales to such a huge number of servers that it is inconsequential as a practical matter.
It also depends on your workload. The types of workloads that benefit most from private data infrastructure are large-scale data-intensive workloads. If your day-to-day is sling tens or hundreds of PB of data for analytics, the economics of private data infrastructure is extremely compelling.
The biggest problem the cloud solves is hardware supply chain management. To realize the full benefits of doing your own build at any kind of non-trivial scale you will need to become an expert in designing, sourcing, and assembling your hardware. Getting hardware delivered when and where you need it is not entirely trivial -- components are delayed, bigger customers are given priority allocation, etc. The technical parts are relatively straightforward; managing hardware vendors, logistics, and delivery dates on an ongoing basis is a giant time suck. When you use the cloud, you are outsourcing this part of the work.
If you do this well and correctly then yes, you will reduce costs several-fold. But most people that build their own data infrastructure do a half-ass job of it because they (understandably) don't want to be bothered with any of these details and much of the nominal cost savings evaporate.
Very few companies do security as well as the major cloud vendors. This isn't even arguable.
On the other hand, you will need roughly the same number of people for operations support whether it is private data infrastructure or the cloud, there is little or no savings to be had here. The fixed operations people overhead scales to such a huge number of servers that it is inconsequential as a practical matter.
It also depends on your workload. The types of workloads that benefit most from private data infrastructure are large-scale data-intensive workloads. If your day-to-day is sling tens or hundreds of PB of data for analytics, the economics of private data infrastructure is extremely compelling.