David Merrill

Long-term Digital Retention Economics (part 2)

Blog Post created by David Merrill on Jan 11, 2017

In my last post, I setup the problem/opportunity analysis to compare very long-term costs (up to 100 years) of different media types that can be candidates for long-term archive.  We will continue with that comparison.

 

In my original work on this topic in 2014, a table was built to show qualitative differences of the total costs of different media types, over time. In my upcoming version of this paper will have this same table, and here is a sneak peek at the results:

 

 

Relative Costs for 100 years

 

Disk

Tape

Optical

Public Cloud

Priv Cloud

Depreciation

High

High

Med

n/a

Med

Subscription

n/a

n/a

n/a

High

Med

HW Maint.

Med

Med

Med

n/a

Very low

Software Maint

Low

Low

Very low

n/a

Very low

Labor

Low

Low

Low

n/a

Very low

Environmentals

Low

Low

Very Low

n/a

Very low

Migration

High

High

None

High

Med High

CSP Fatigue

n/a

n/a

n/a

High

Med

On-boarding

Very Low

Very low

Very low

Med High

Med

Off-boarding

n/a

n/a

n/a

Med High

Med

Usage limit

n/a

n/a

n/a

Medium

Low

Network

Low

Low

Low

Medium

Low

Elasticity

Low

Low

Low

High

Medium

MTTR

High

Low

Medium

Medium

High

Outage Risk

Low

Medium

Med-Low

Med-Low

Low

Risk of Loss

Low

Low

Low

Low

Low

 

This table approach above lends itself to an alignment graph (spider chart) to contrast the qualitative and economic benefits of each technology option. For this graphic, and for the sake of clarity, I am only showing the qualitative comparison of Tape, Optical storage and public cloud.

 

Picture1.jpg

 

On the graph above, higher numbers are better. Now we can see volumetric views of the goodness of 3 different media/architecture types against the backdrop of 10 comparison areas. The larger the surface area in the graph, the better the media/architecture meets the overall requirements

  • Public cloud is best in the upper right areas (low subscription rate, maintenance, labor and environment built into the subscription price). But on-boarding and over-use fees, with high network costs make it shallow on lower left cost areas
  • Tape is better for lower left area
  • Optical has a better, balanced TCO footprint.

Not all of these above costs are equal in weight over time. For example with Krieder’s law in effect, the price of the media will essential be near-zero over time, whereas usage tariff or migration costs will constitute the bulk of long-term costs. We can now take the spider diagram, overlay individual client requirements on top to get a basic fit-check.

 

With a qualitative comparison and biasing complete with a customer, we can now apply IT economics. These 10 areas can now be computed, weighted, filtered and applied to a particular vertical market or customer needs basis. My 3rd and final blog entry on this subject will present some of the quantitative analysis comparing different media types and architectures to a long-term time horizon. 

Outcomes