# HDD Native Parallel Filesystem: Maximizing Throughput for Highest Capacity CMR and HM-SMR Drives

- Institution: CERN
- Speaker: Piotr Modrzyk
- Year: 2026
- Language: English
- Subjects: Computer science
- Source: [CERN](https://videos.cern.ch/record/3025504)
- Licence: [CERN](https://copyright.web.cern)
- Who can watch: Tweens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

As HDD capacities reach tens of terabytes while per drive IOPS remain largely unchanged, conventional SDS designs often hit IOPS limits before achieving full sequential bandwidth. This imbalance frequently leads operators to choose smaller disks in an attempt to balance capacity and performance. Leil Storage addresses this challenge with a sequential access model that aligns I/O patterns with the natural behavior of HDDs, making the approach truly HDD native. This enables sustained maximum throughput on high capacity CMR and HM-SMR drives alike. Using SaunaFS as a reference, we describe the architectural changes required to meet HM-SMR constraints, including zone appends, zone cleaning, and the elimination of in place rewrites, while preserving both performance and reliability.

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## Lectures

1. [HDD Native Parallel Filesystem: Maximizing Throughput for Highest Capacity CMR and HM-SMR Drives](https://invisiblenetwork.ai/learn/cern/3025504/70246321a7b8), 15 min (CERN's player)