It is all about location, location, location!

The analysis of cloud versus on-premises LTO is not simple. The relative costs depend on so many factors, including how much content is to be retained and how many retrievals are likely to be needed. Those factors are expected but, for many, the big surprise is the dramatic impact of location.

Many XenData customers are in the media and entertainment industry. They rarely want to delete their content, have long term storage requirements and their storage volumes are often measured in petabytes. Consequently, my analysis centers on an organization that has 1 PB of video and image files and it compares AWS Deep Glacier and a XenData LTO XQ8 archive system which stores and manages content on LTO-9 cartridges retained ‘on the shelf’.

Costs for 1 PB stored in AWS Deep Glacier are heavily dependent on the location of the AWS data center. Of course, choosing a data center close by means that you will obtain good transfer rates. Here are some basic storage costs in US dollars for 1 PB, excluding any restore fees, for some different locations:

This clearly illustrates the significant differences in AWS Deep Glacier storage costs by region. AWS Deep Glacier costs increase further when we add restore fees. As an example, the total costs when restoring 1% of the archived content per month (10 TB) with standard priority via the Internet are shown below.

* Note – Standard restores take 12 hours after the instruction to rehydrate to an accessible storage tier.

Turning now to an on-premises system, the XenData XQ8 is a turnkey archive system which automates many aspects of archiving to LTO.

The XQ8 includes an intelligent appliance and a small robotic library. It minimizes the need for human intervention and manages LTO tapes using barcode labels applied to the cartridges. And for extra data protection, it will automatically generate duplicate LTO cartridges.

Total cost over 5 years is broken down as follows:

* Note – uses 98% utilization per LTO-9 cartridge and 1 PB = 1,125,899,906,842,620 bytes.

The cost per year is $10,415 with little dependency on location and no dependency on volume of restored files. This includes the cost of duplicate LTO cartridges for extra data protection.

When comparing AWS Deep Glacier with on-premises LTO, there are other factors to consider:

• Deep Glacier is an operating expense; LTO is mainly a capital expense.
• LTO requires a person to be on premises to restore files.
• Deep Glacier requires 12 hours to bring files back online whereas LTO takes less than 10 minutes if a person is available to pull the required LTO cartridge from the shelf.
• The Deep Glacier costs scale linearly. When doubling the archived capacity to 2 PB, the Deep Glacier costs almost double. But for LTO, they increase by 30% which is the cost of the additional LTO cartridges to double the archive capacity.
• The analysis given above assumes restore rates of 1% of the total archived volume per month. Deep Gracier costs grow rapidly for higher restore rates.
• When the system is decommissioned, there is a significant cost to restore the 1 PB from AWS, unlike LTO.

In summary, AWS data centers located in the USA offer better cloud storage rates for long term archiving than other AWS locations. But, even at AWS US storage rates, a 1 PB LTO on-premises system offers a much lower cost. For an archive with 1% monthly restore rates, LTO is only 40% of the annual cost of AWS Deep Glacier. In other regions, LTO provides an even larger cost advantage. An extreme example is Sao Paulo, Brazil where a 1 PB archive in Deep Glacier costs nearly six times as much as an on-premises LTO.

Reference

AWS S3 Pricing Calculator: Create estimate: Configure Amazon Simple Storage Service (S3)

XenData XQ8 LTO Archive System – Link