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November 13, 2025

Why the “Three Archive Tiers” Don’t Cut It: Leil's Tierless BEST Approach

Introduction

The Active Archive Alliance recently defined three archive tiers – WORM (Write Once, Read Many), WORSe (Write Once, Read Seldom), and WORN (Write Once, Read Never) – to manage diverse archival needs driven by AI and big data analytics. These tiers reflect growing complexity in balancing performance, cost, and access frequency across multiple storage media like SSDs, HDDs, tape, and optical. A great article on this was published by Chris Mellor from Blocks and Files recently. Having read the article, and having had the very long day today with a few thought-provoking calls, I decided to leave some traces in writing on how we, at Leil, see this.

To us, this multi-tiered complexity is a symptom of legacy storage constraints rather than a necessity. Organizations often struggle with managing separate silos and complicated policies across tiers, especially as data access patterns rapidly evolve.

Leil fundamentally redefines this landscape. It is easy to explain when you do not try to be what you are not. It was not our original idea or master plan to be that kind of product. Moreover, people following us since 2023, might witness this evolution happening in front of their eyes as we were drifting from cold, to archive, to active archive and finally to nearline. This was not a simple change of words to look “better”. This was and is the result of the hard engineering work – changing the architecture, key modules, core functions, optimizing performance and a lot more that’s always remained under the hood. This is unpleasant daily routine of sweat, hard talks, outages and all of that not making it to shiny press releases. Objective reality behind your typical marketing bullshit bingo. And here we are – pushing the drives and enclosures with our software to the theoretical possible maximum that hardware can provide. How cool is that? It’s cool externally. Internally, it’s endless nerves and hustle and dedication.

Leveraging high-density, SMR HDDs and a HDD-native architecture for large-scale deployments, Leil now collapses all archive types – from deep cold archive, traditional tape workloads, to active archive and nearline – into one unified, tierless storage tier. This single HDD-native tier delivers exceptional scalability, resiliency, performance, and affordability that even tape cannot match, while offering performance that hits the limits of PCIe bus and energy efficiency, dropping the power bill.

The simplicity of this tierless concept means fewer operational headaches, no complex policy tuning, and essentially “one storage tier to rule them all.” Concept is not novel and we do not pretend to have invented it. Our humble efforts are just to enable this for the ocean of HDD world. The Leil approach, powered by proprietary software and the SaunaFS open source distributed file system, achieves:

  • Capacity exceeding conventional archives and tapes at exabyte scale
  • Performance enabling instant analytics and AI on data lakes
  • Resiliency with robust data protection and erasure coding schemes
  • Sustainability via up to 70% energy savings using power-disable and intelligent data grouping
  • Affordability that beats tape on its own cost turf

To capture this vision, Leil Storage follows the BEST principle: Built for Efficiency, Scalability, and Tierlessness – a true Tierlessness that removes complexity by unifying HDD storage into one powerful, green, and affordable native HDD tier.

When you evaluate storage strategies, ask yourself: why settle for legacy complexity and patchwork tiers when BEST tierless storage delivers unmatched simplicity, performance, and cost savings?

SC25 is coming and our team is ready to talk in details on what we’ve got to offer. No ridiculous NDAs to even show the product in action, see the code and talk to actual developers, no hidden catch and no wildcards in the terms. 

Technological innovations can be simple when they are not smoke and mirrors.

Author: Alexander Ragel
Alexander Ragel is the CEO of Leil, an Estonia-based storage infrastructure company building HDD-native software for the exabyte era. Leil is in active co-engineering partnership with Western Digital, validated across the WD, Seagate, and Toshiba drive ecosystems.