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Leil
SERVER SIMPLY + Leil
What Is Leil — and How SERVER SIMPLY Delivers Complete HDD-Native Storage Infrastructure
Leil is an HDD-native storage operating system for large-scale, energy-efficient on-premises data storage. SERVER SIMPLY designs, validates, delivers and supports the complete infrastructure around it — storage servers, drives, networking, rack design, power planning, validation, delivery and long-term expansion.
- Complete Leil infrastructure solution
- Architecture, hardware, validation, delivery
- Up to +25% usable capacity gain vs. generic SDS*
- Lower power per stored TB
*Representative architectural metrics based on verified SMR optimizations.
What is Leil?
Leil is an HDD-native storage operating system for large-scale, energy-efficient on-prem data environments. It manages modern HDD behaviour directly — HM-SMR zones, drive health, power states, I/O scheduling and self-healing recovery — instead of treating drives as generic block devices. SERVER SIMPLY helps companies deploy Leil as a complete infrastructure solution, providing the storage servers, drives, networking, rack planning, power and cooling considerations, validation, delivery and long-term expansion planning needed to run Leil in real production environments.
HDD-native storage software
Leil is built around the physical behaviour of high-capacity HDDs — CMR and host-managed SMR — rather than abstracting drives into generic block devices. The result is higher storage density, better usable capacity and lower energy footprint per stored TB.
Standard file protocols
Even with HM-SMR underneath, Leil exposes data through native POSIX and NFS, with SMB and S3 gateways from a single namespace. Existing applications and workflows connect to Leil without code changes, custom drivers or proprietary clients.
Why Leil matters
Data volumes keep growing while power, rack space and budgets stay constrained. Public cloud helps short-term but introduces escalating egress fees, unpredictable pricing at scale and data sovereignty concerns. Leil addresses these pressures directly — at the storage software layer — and SERVER SIMPLY turns it into a deployable infrastructure.
Growing data volumes
Backup, archive, AI training data, media and IoT ingest are all growing into petabyte and exabyte territory. Generic SDS stacks were not designed for this density profile.
Cloud cost and egress fees
At scale, storing data in public cloud becomes significantly more expensive than on-prem, especially when data is read back regularly for AI, analytics or media workflows.
Data sovereignty
Many organisations need full control over where data lives, who has access and how it is governed — requirements that are easier to meet on-prem than in shared cloud regions.
Power and rack-space limits
Data centres are increasingly constrained by available power and rack density rather than by raw capital budget. Density and watts per stored TB become the deciding factors.
Self-healing infrastructure
Leil treats HM-SMR as the foundation, not an exception — managing zones natively, isolating failed platter surfaces and reducing operational toil at multi-petabyte scale.
Predictable economics
Flat-rate Leil OS pricing combined with planned hardware expansion gives finance teams a multi-year cost model without surprise scaling fees.
SERVER SIMPLY builds the complete Leil infrastructure stack
Leil creates the software capability. SERVER SIMPLY builds the validated and manageable infrastructure around it — designing, delivering and supporting the complete environment Leil runs in. From high-density JBOD enclosures to full storage servers, we work with customers from initial workload validation all the way to long-term capacity expansion, so Leil is delivered as a production solution, not just a hardware list.
Architecture and sizing
We translate capacity, throughput, resilience and growth targets into a concrete reference architecture matched to the Leil software layer.
Storage server and JBOD selection
Right chassis, drive bays and controller configuration matched to capacity, density and power targets — including JBOD expansion for petabyte-scale Leil deployments.
HM-SMR and CMR drive planning
We plan the right CMR and HM-SMR drive mix based on workload and density targets, and source validated drives for the deployment.
Networking and connectivity
Network interconnects configured for replication, erasure coding and client access throughput requirements at petabyte scale.
Rack design, power and cooling
Hardware layouts planned to fit within data centre power, cooling and rack density limits at multi-petabyte scale.
Validation and delivery
Hardware validated before delivery so the Leil software deploys onto a known-good, production-ready platform.
Deployment support
Hands-on support during the initial deployment phase, working alongside customer teams and Leil software engineers.
Long-term expansion planning
Compatible nodes and drives planned ahead, so capacity growth happens without re-architecting the cluster.
Workload validation
We validate that the workload — backup, archive, AI, media — actually fits a Leil-based architecture before any hardware is committed.
Ready to plan a petabyte-scale storage architecture? SERVER SIMPLY validates your workload before any hardware is committed.
Request a Leil Infrastructure DesignHow Leil and SERVER SIMPLY work together
SERVER SIMPLY designs, builds, validates and supports the infrastructure. Leil provides the storage software that runs on it — managing HM-SMR drives, distributing data and exposing standard file protocols. Neither side delivers the complete solution alone.
Infrastructure by
SERVER SIMPLY
Architecture, servers, drives, networking, rack, power, validation, delivery, expansion
+
Software by
Leil
HM-SMR management, erasure coding, file protocol gateways
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Complete solution
Leil-based storage
High-density, power-efficient on-prem storage delivered as a managed solution
| Layer | Provided by | What it covers |
|---|---|---|
| Storage software | Leil | HM-SMR management, distributed file system, erasure coding, snapshots, multi-protocol access |
| Hardware platform | SERVER SIMPLY | Storage servers, CMR and HM-SMR drives, networking, controllers, validated builds |
| Infrastructure design | SERVER SIMPLY | Reference architecture, sizing, rack design, power and cooling planning |
| Delivery and validation | SERVER SIMPLY | Pre-delivery validation, deployment support, long-term expansion planning |
| Complete solution | SERVER SIMPLY + Leil | A production-ready, on-prem, large-scale storage environment |
Inside the Leil software layer
Leil runs on the SERVER SIMPLY hardware foundation and handles HM-SMR drive management, data distribution, resilience and file access. It turns storage servers into a unified, scalable platform.
Powered by the SMRT Engine
Leil's purpose-built technology layer autonomously manages HM-SMR zones, drive health and power efficiency, delivering self-healing infrastructure without manual intervention.
HM-SMR drive management
Handles the sequential write model that HM-SMR requires, so applications interact through standard file protocols.
Distributed POSIX file system
Built on Leil FS, Leil's open-core parallel file system strictly optimized for high-capacity HDDs.
Erasure coding
Improves usable capacity efficiency versus replication while maintaining resilience across nodes.
Multi-protocol access
Native POSIX and NFS, with SMB and S3 gateways from a single namespace.
Snapshots and immutability
Copy-on-write snapshots for fast recovery points and ransomware protection workflows.
Mixed-drive support
CMR and HM-SMR drives in the same cluster for a gradual adoption path.
Head Depopulation
Instead of replacing entire failed drives, Leil isolates only the affected platter surface, preserving ~95% of drive capacity with zero-downtime recovery.
Command Duration Limits (CDL)
Enforces strict I/O deadlines — if a drive misses its deadline, Leil instantly reconstructs data from parity, eliminating tail latency that disrupts AI training and streaming workloads.
Deploys in hours
Standard Linux package repositories (Debian, Ubuntu, Rocky Linux, Fedora) — no kernel patching, custom firmware, or driver conflicts.
Beyond software-defined storage
Leil doesn't just manage storage pools — it takes over hardware-level functions that firmware traditionally handles, resulting in a self-healing infrastructure layer. Leil operates as a hardware-native OS:
- Manages drive regeneration
- Controls power states
- Handles I/O scheduling
- Enables self-healing infrastructure
Where Leil fits best
Leil is optimized for write-sequential and read-any workloads — which covers the majority of enterprise data growth. SERVER SIMPLY validates each workload against a Leil-based architecture before any hardware is committed, so customers move into production with confidence.
AI training data and HPC warm tier
AI training and HPC workloads create enormous training libraries that are written once and consumed many times across model training, evaluation and re-training cycles. All-flash storage is rarely cost-effective at exabyte scale, and public cloud egress fees make repeated reads punishing. Leil is well suited to this warm-tier role: HM-SMR delivers the density and watts-per-TB efficiency required, while POSIX, NFS and S3 access let GPU clusters and data pipelines connect without changes. SERVER SIMPLY designs and delivers the AI-side storage infrastructure — sizing the cluster, planning network throughput between the storage tier and GPU compute, validating drives and controllers, and integrating the platform with existing AI and Deep Learning infrastructure. Customers get a warm-tier storage layer that feeds high-performance NVMe and GPU compute reliably, scales with the model roadmap and stays inside on-prem budgets even as datasets grow into the exabytes.
Backup and active archive storage
Backup and archive remain the largest single driver of storage growth in most enterprises. Backup targets ingest large volumes of sequential data overnight, retain it for weeks or months, and occasionally read it back for restores or compliance. Active archive workloads keep older data online and searchable rather than pushing it to tape, so it can be retrieved on demand without an operator workflow. Both patterns map perfectly onto Leil's HM-SMR-native design: high density, append-first ingest, predictable read performance and cost-efficient long retention. SERVER SIMPLY designs the full backup or archive infrastructure around Leil — including the storage servers, drives, networking, rack design, power planning and validated delivery — and helps customers plan capacity expansion as retention windows grow. The result is an on-prem backup and archive tier with cloud-scale density and predictable economics, without the egress fees, retention surprises or sovereignty concerns of a public-cloud archive.
Media, broadcast and content storage
Broadcasters, post-production studios, content platforms and research imaging teams all share the same problem: very large media libraries that must remain online, be played back or rendered on demand and grow continuously over time. These workloads are sequential by nature — large file writes, mostly read-back access, long retention — which is exactly the workload profile Leil is built for. SERVER SIMPLY designs the media-storage backbone around Leil: high-density storage servers, network throughput sized for parallel readers, rack and power planning for multi-petabyte content libraries, and a validated platform ready for the Leil software layer. The combination delivers a media origin or content archive with cloud-scale density on-prem, predictable cost per stored TB and the multi-protocol access (POSIX, NFS, SMB, S3) that media production tooling expects, without the per-GB egress fees of a cloud-based content archive.
Surveillance and IoT ingest
Surveillance platforms, smart-city deployments and industrial IoT systems generate continuous, high-volume sequential writes from cameras and sensors, with retention requirements that often span years for compliance, investigation or analytics use cases. Generic SDS platforms struggle with both the ingest pattern and the long-term economics. Leil handles this naturally: HM-SMR-native storage, sequential write optimization, erasure coding for resilience and standard file protocols for the recording and analytics tools on top. SERVER SIMPLY builds the supporting infrastructure — storage servers sized for sustained ingest, networking that absorbs camera or sensor streams without bottlenecks, rack and power planning for long-retention deployments and validated hardware ready for production. The result is a surveillance and IoT storage backbone that ingests reliably 24×7, scales as the deployment grows and keeps long-retention data accessible without the cost or sovereignty trade-offs of public-cloud surveillance archives.
Research data and scientific archives
Research institutions, genomics teams, scientific computing groups and large-scale simulation environments need to store and re-access very large datasets over long periods, often with strict reproducibility and retention requirements. The data is mostly written once, then read repeatedly across analysis cycles, collaborations and publications — a near-perfect match for Leil's design. SERVER SIMPLY designs research-grade storage infrastructure around Leil, planning the cluster for sustained read throughput, sizing drives and controllers for long-life datasets, and integrating the platform with HPC schedulers, analysis pipelines and existing campus networks. Validated hardware, multi-protocol access and predictable cost-per-TB make Leil a strong foundation for scientific archives that must remain online for decades while still scaling alongside instrumentation and simulation output.
When Leil is not the right fit
Leil is not meant to replace every storage tier. For latency-critical databases, transactional systems or random-write-heavy virtualisation workloads, NVMe, all-flash or hybrid storage is usually a better fit. SERVER SIMPLY validates the workload before any hardware is committed and recommends the right storage tier for each use case — including configurations outside the Leil platform when that better serves the customer's goals.
Why HM-SMR matters for this solution
Host-managed SMR increases capacity per drive by shingling tracks. The trade-off is sequential writes. In return: more usable capacity per rack unit and lower power per stored TB — which becomes decisive at multi-petabyte scale. With business context already established, the technical trade-off is straightforward.
Higher density per drive
Fewer drives, fewer servers and less rack space for a given usable capacity target.
Lower power per stored TB
At multi-petabyte scale, reduced watts per TB directly improves long-term economics.
Software handles the complexity
Leil manages the SMR write model so applications use standard file protocols without changes.
Gradual adoption
Start with conventional CMR drives and add HM-SMR over time as workload validation confirms fit.
| Approach | Optimises for | Trade-offs | Best fit |
|---|---|---|---|
| Tape archive | Lowest media cost for very cold data | Retrieval latency and workflow complexity | Long-retention compliance archives |
| Cloud object storage | Convenience and global reach | Escalating egress fees, unpredictable costs at scale, data sovereignty concerns | Smaller datasets with global access requirements |
| All-flash archive | Fastest random access | Higher cost per TB | High-value datasets with frequent random reads |
| Leil (SERVER SIMPLY + Leil) | Density and power per TB | Best for write-sequential, read-any workloads; not ideal for random-write-heavy databases or VM storage | Backup, archive, AI/HPC warm tier, media, sequential data lakes |
Energy efficiency and the Infinite Cold Engine roadmap
SERVER SIMPLY infrastructure combined with the Leil software layer already improves power per stored TB. Leil's Infinite Cold Engine delivers 25% energy reduction today through software-controlled intelligent spin-down, with a roadmap to 70% reduction. Results vary by workload and access pattern.
Available today
HM-SMR on SERVER SIMPLY infrastructure improves power per stored TB and storage density. Infinite Cold Engine delivers 25% energy reduction through intelligent spin-down.
Roadmap: Advanced ICE
ICE will power down idle drives when access patterns allow, targeting 70% energy reduction while keeping data online at lower energy cost.
Deployed in production
Leil runs in mission-critical environments handling petabyte-scale data across industries.
National broadcaster
Multi-PB video-on-demand origin storage powering content delivery at national scale.
Regional hosting leader
Enterprise file sharing platform supporting tens of thousands of users with high-availability requirements.
Research institution
Long-term archive for scientific datasets requiring immediate access and multi-decade retention.
AI training infrastructure
Exabyte-scale warm tier feeding GPU clusters with training data and model checkpoints.
Reference configurations
Directional planning inputs based on published specifications. SERVER SIMPLY sizes the right configuration for each environment as part of the complete solution.
1.5 PB
Standard
Scale-out design with a smaller initial footprint.
11.5 PB
Advanced Green
Higher density for stronger power efficiency per TB.
19.5 PB
Enterprise Green
Very large-scale density and operational repeatability.
~0.5 W
Power per usable TB
Enterprise Green directional benchmark.
POSIX / NFS / SMB / S3
Access model
Native POSIX and NFS, with SMB and S3 gateways from a single namespace.
99.9%
Published SLA
Service availability reference.
Unlimited
File system size
No artificial scale ceiling.
24x7x365
Support
Enterprise deployment support posture.
Pricing
Predictable, transparent pricing with no hidden costs or scaling surprises.
Leil OS pricing
Starts from EUR 0.99/TB/month — flat-rate, all-inclusive, with no egress or retention fees. Predictable scaling from terabytes to exabytes.
No lock-in
Leil OS is built on Leil FS, an open-source GPL-3.0 project. Your data is never locked in.
FAQ
What is Leil?
Leil is an HDD-native storage operating system for large-scale, energy-efficient on-prem data environments. It manages modern HDD behaviour directly, including HM-SMR zones, drive health, power states, I/O scheduling and self-healing recovery.
Can I buy Leil through SERVER SIMPLY?
Yes. SERVER SIMPLY provides the complete infrastructure side of Leil-based deployments — storage servers, drives, networking, rack planning, validation, delivery and long-term expansion planning.
Does SERVER SIMPLY only sell hardware?
No. SERVER SIMPLY designs and delivers complete infrastructure solutions. For Leil projects, this includes architecture, sizing, hardware selection, validation, deployment planning and future expansion — not just a hardware list.
What kind of companies should consider Leil?
Leil is relevant for organisations with large and growing data volumes — backup providers, hosting companies, research institutions, AI infrastructure teams, media companies, surveillance platforms and enterprises with active archive needs.
Is Leil a cloud storage service?
No. Leil is designed for on-premises or controlled data centre infrastructure. It is an alternative for organisations that want cloud-scale storage efficiency without moving all data into the public cloud.
Is HM-SMR good for databases or VMs?
Usually not. HM-SMR needs sequential writes. SERVER SIMPLY validates workload fit before any hardware is committed and recommends a different storage tier when Leil is not the right match.
Can I start with conventional drives?
Yes. Leil supports mixed CMR and HM-SMR drives. Start with conventional drives and add HM-SMR later as workload validation confirms fit.
Do clients need to change how they access data?
No. Leil exposes data through native POSIX and NFS, with SMB and S3 gateways from a single namespace, so existing tools and workflows connect without changes.
How does Leil pricing work?
Leil OS pricing starts from EUR 0.99/TB/month, flat-rate with no egress or retention fees. No hidden costs as you scale.
Is my data locked into Leil?
No. Leil OS is built on Leil FS, an open-source GPL-3.0 project. Your data remains accessible through standard protocols.
Plan a complete Leil-based storage solution with SERVER SIMPLY
Leil delivers the storage software capability. SERVER SIMPLY designs, validates, delivers and supports the complete infrastructure around it — so the result is a working, large-scale on-prem storage solution, not just a hardware list.
- Workload validation before any hardware is committed
- Architecture, hardware, networking, rack and power planning
- Validated delivery ready for the Leil software layer
- Long-term expansion planning to multi-petabyte scale
