Public cloud Hotel California costing exposed

Storing a petabyte of data in an Amazon file system can cost 400 per cent more per month than storing it in an on-premises all-flash file store, and moving it back on premises can cost tens of thousands of dollars. Cloud suppliers want to stop customers moving their data out.

The data behind these claims was sourced, calculated and presented by William Blain financial analyst Jason Ader, who looked at the Amazon Elastic File System (EFS). This has an approximately 13x multiple over S3 — costing $0.30/GB vs S3’s $0.023/GB. Ader cites a 2020 Nutanix Cloud Usage report to show that EFS accounts for roughly 25 per cent of storage spending from enterprise and commercial AWS customers. 

Ader told subscribers: “As a general rule, based on our research, any amount of production data (data that needs a minimum level of performance) above one petabyte will be substantially less expensive to host in an on-prem data center versus the cloud.”

He shows a worked example in a table:

This table shows that storing a petabyte for one month in Amazon’s EFS vault will cost $300,000 whereas storing it on-premises in an all-flash store with a full-time storage admin person and a replicated copy of the data will cost $58,333.3/month — 19.44 per cent of the AWS EFS cost. The on-premises cost is calculated using IDC data for average AFA cost per GB.

The AWS EFS costs do not include include multiple region hosting, which will increase them significantly, possibly double. Nor do they include snapshots or ingress/egress costs, which will increase the amount. The egress pricing can be particularly high and Ader has another table showing this:

The 500GB egress costs are extraordinarily high and, Ader supposes, “These fees appear intended to dissuade customers from leaving the fold, and reinforce the cloud lock-in risk of which many enterprises are wary.”

Customers with a strategy of using multiple public clouds will face costs when moving data between them. The 2021 Flexera State of Cloud report indicates that 92 per cent of enterprises are currently leveraging a multi-cloud approach and that 80 per cent are using a hybrid cloud strategy (average of 2.6 public clouds and 2.7 private clouds).

He sums it up by saying: “It is important for customers to take egress costs into account when planning cloud migrations and multi-cloud strategies. In particular, the costs of moving data between different clouds or between the cloud and on-premises data stores as part of a multi-cloud application can be non-trivial.” Looking at the table above, you better believe it.