An Economic Perspective of Disk vs. Flash Media in Archival Storage

Abstract

For three decades, Kryder's law correctly predicted an exponential increase in bit density on disk platters, leading to an exponential drop in cost per gigabyte, and thus to an entrenched expectation that if data could be stored for a few years the incremental cost of storing it forever would be minimal. However, disk now is over 7 times as expensive as Kryder's law would have predicted, and industry projections suggest that in 2020 the gap will reach 200 times, disrupting this expectation.Our model shows that archives based upon alternative media are surprisingly cost competitive with archives based upon traditional disk media over the long-term. We propose using Archival Flash for long-term data preservation, with the trade off between longer data retention period and lower write cycles.

Collecting, exploring and sharing personal data: Why, how and where

“…Other study highlighted that over the long term owning the infrastructure can save money [88]. Finally, researchers that studied the endowment model over a 100 years simulated archive founded that SSDs are a better choice media to keep the costs low [89].…”

Effects of prolonged media usage and long-term planning on archival systems

“…We also tested SSD characteristics since it had been shown that flash may be suitable for archival storage over time while keeping the costs comparable to traditional disk archives [31]; also there is increasing interest in designing flash to be used for archival purposes [21] and industry is looking at incorporating flash in their archival storage systems [26,55].…”

“…Storage costs are approximately one third of the total system's cost [41,46], and they are going to be more important in the future as the annual media density growth rate (Kryder's rate, or K r ) continues to decrease [31,46]. In times of highly increasing media density growth, it was cost-effective to replace media before the manufacturer-supplied endof-life, and not much thought was given to the planning duration or using media for an extended period of time.…”

“…In times of highly increasing media density growth, it was cost-effective to replace media before the manufacturer-supplied endof-life, and not much thought was given to the planning duration or using media for an extended period of time. However, as media reach their technical limits, and media density growth slows down, or stops [31,46], the total costs of preservation would increase further.…”

Gloria

“…For all other uses, contact the owner/author(s). time, price per unit of storage on commodity hardware has been seeing a significant decrease as suggested in [15], enabling new use cases.…”