Designing distributed file systems that deliver local performance without sacrificing consistency, control, or operational simplicity remains a persistent challenge in enterprise systems engineering. Centralized file storage remains the preferred model for governance, security, and data lifecycle management; however, the users and applications that depend on this data are increasingly distributed across branch offices, global regions, and hybrid cloud environments.
The tension between centralized storage and distributed access isn’t just a theoretical issue — it shows up every day in the form of sluggish file operations, frustrated users, fragile workarounds, and increasingly complex infrastructure built to patch over deeper architectural limits. For example, a remote team trying to open or sync large design files from a central server often runs into long load times, version conflicts, or unreliable VPN connections, turning what should be a simple task into a daily productivity drain. File Caching with Resilio Active Everywhere (formerly Resilio Connect) distributed data movement platform, addresses this problem by treating file access as a distributed systems concern rather than a networking optimization exercise.
This article examines why file caching is the ideal architectural primitive for modern environments, how Resilio implements it, and why engineering teams prefer Resilio over legacy hub-and-spoke solutions.
Why Protocols Fail Over WANs
From an engineering perspective, file access performance over distance fails for a simple reason: file protocols were designed with low-latency networks in mind. Protocols such as SMB and NFS are not streaming protocols; they are stateful, metadata-heavy, and dependent on frequent round-trip for correctness. Even in their modern incarnations, they require repeated exchanges for permission checks, file opens and closes, directory traversal, locking semantics, and metadata validation.
When these operations occur over a WAN, latency and packet loss, not bandwidth, become the dominant factor. A single user action can trigger dozens or hundreds of round-trip requests, each paying the full cost of WAN latency. The result is disproportionately poor performance that no amount of throughput can fix. This is why even well-provisioned WAN links fail to deliver acceptable file performance for engineering workloads, build systems, and content pipelines.
Resilio’s approach compensates for WAN latency from the file protocol path entirely by terminating SMB or NFS locally at the edge. Once data is cached, file protocol operations occur entirely within the LAN, restoring the assumptions that applications implicitly rely on. This architectural decision is foundational: Resilio does not attempt to “optimize” file protocols over the WAN; it eliminates the need to traverse the WAN for most operations altogether.
Replication vs File Caching: Architectural Tradeoffs
Replication is often positioned as the natural answer to distributed file access, but at scale, it introduces structural complexity that is difficult to justify. Replicating complete datasets to every site multiplies storage consumption, increases backup and recovery costs, and requires careful capacity planning at locations that may only access a small subset of the data.
More critically, replication introduces consistency challenges that grow exponentially as the number of writable replicas increases. Conflict resolution, version divergence, and split-brain scenarios are not edge cases; they are inherent properties of distributed write systems. Managing them requires additional tooling, operational discipline, and tolerance for ambiguity during failure conditions.
The Resilio approach to File Caching deliberately avoids these problems by enforcing a single authoritative data source. The primary storage system remains the sole owner of file state, metadata, and permissions. Edge locations do not become peers in a multi-writer system; instead, they serve as performance accelerators. Cached data is validated against the primary source and can be discarded and rebuilt at any time without compromising data integrity. This dramatically simplifies failure handling, operational recovery, and architectural reasoning.
File Caching for Modern File Access
File caching is not a compromise between performance and control; it is a way to decouple them. By separating where data is stored from where data is accessed, caching enables local performance without duplicating responsibility for correctness.
In our architecture, the primary storage system retains full authority while caching gateways serve as local access points. These gateways present files using standard protocols, maintain a disk-based cache of active data, and fetch content on demand using the optimized transport layer built into Active Everywhere. To applications and users, the experience is indistinguishable from a local file server. To administrators and architects, the data model remains centralized and predictable.
This distinction matters operationally. A cache is not a replica; it does not require protection, reconciliation, or recovery. If a gateway fails, another gateway can take over. If a cache becomes corrupted or undersized, it can be rebuilt. There is no ambiguity about which copy of a file is correct.
How Resilio Implements File Caching
Resilio File Caching is delivered as part of the Resilio Active Everywhere distributed data movement platform and is entirely software-defined. It integrates with existing storage systems rather than replacing them and runs on standard operating systems in virtualized, cloud, or bare-metal environments.
At the core of the system is a peer-to-peer transport engine designed for long-distance and high-latency networks. Instead of relying on SMB or NFS over distance, Resilio transfers data in parallelized chunks, dynamically adapts to changing network conditions, and encrypts data in transit.
Caching gateways can be deployed individually or grouped into scale-out clusters. In a scale-out configuration, nodes share cache population and provide high availability without introducing centralized bottlenecks. Horizontal scalability is critical in environments where performance requirements increase over time or where resilience is a top priority.
Consistency, Correctness, and Trust
Performance is only meaningful when data integrity and consistency are preserved. For engineers, the critical question is not just how fast a system is, but what guarantees it provides under normal operation and failure conditions.
Resilio File Caching enforces strong read consistency relative to the primary storage. Cached data is validated before it is served, and changes on the primary invalidate stale cache entries, ensuring that every cached file reflects the latest version from the authoritative source. There is no reliance on time-based heuristics or eventual consistency models that silently serve outdated data. This makes the system suitable for regulated environments, building pipelines, and engineering workflows where correctness cannot be traded for speed.
By maintaining a clear boundary between authoritative data and cached data, Resilio avoids the subtle failure modes that plague distributed write systems. Software engineers and DevOps can reason about system behavior under failure without needing to account for reconciliation logic or conflict resolution.
Failure Modes and Operational Simplicity
Our architecture is designed to handle failures predictably and safely. If a caching gateway goes offline, users automatically reconnect to another gateway in the same cluster. If a WAN link is disrupted, cached data remains available locally. And if the primary storage experiences an outage, recovery follows your existing backup and disaster recovery processes; no special procedures are required for cached data.
This predictable behavior makes the system easier to manage. It reduces downtime, simplifies incident response, and lowers the operational burden on administrators. Cached data does not introduce hidden complexity or unexpected failure modes.
Cache Behavior and Working Set Optimization
Effective caching depends on retaining the right data. Resilio provides policy-driven cache management, allowing administrators to define how cache space is used and reclaimed based on usage metrics and access patterns. Eviction behavior is predictable and transparent, ensuring that frequently accessed files remain local while cold data naturally ages out.
Caching is especially effective for large files, which benefit most from local retrieval rather than repeated WAN transfers. Because the cache represents only the active working set, organizations can deliver high performance at the edge without replicating terabytes or petabytes of infrequently used data. This balance between performance and efficiency is one of the core reasons caching scales more effectively than replication.
Observability and Day-2 Operations
Resilio includes a centralized Management Console that gives operations teams full visibility and control. It provides:
- Cache utilization: Monitor how cached data is being used across gateways
- Transfer performance: Track data transfer rates and efficiency
- Gateway health: See the status of individual caching gateways and clusters
- Job status: Monitor ongoing transfers, updates, and cache operations
For infrastructure and storage operations teams, this translates to faster troubleshooting, more precise capacity planning, and fewer blind spots. The system meets modern expectations for observability, operational control, and proactive management.
How Invetech Replaced NetApp Global File Cache with Resilio File Caching
Invetech, a global biomedical engineering company, modernized its distributed file access by replacing NetApp Global File Cache with Resilio File Caching. With over 240 engineers working across continents and relying on large CAD files and custom design tools like SolidWorks PDM and Altium, Invetech required a faster, more reliable solution for remote file access. Their existing system introduced unacceptable file sync delays and lacked the observability needed for effective troubleshooting.
Invetech previously used NetApp GFC to bridge file access between their Melbourne and San Diego offices. However, the system began showing serious performance issues after a migration. Files took one to two minutes to appear across locations, causing workflow disruptions and user frustration. Support limitations and poor visibility into sync failures made diagnosing problems nearly impossible. With NetApp GFC reaching end-of-service life, Invetech needed a long-term solution that offered consistent file access performance, transparency, and integration with existing infrastructure.
After evaluating alternatives, Invetech deployed Resilio Active Everywhere, which includes File Caching. The platform’s peer-to-peer architecture and UDP-optimized file transfers delivered immediate performance gains. Shared files now appear instantly, and remote users access data as if it were local. Resilio Agents were installed directly onto Invetech’s existing VMware and Dell SAN infrastructure, requiring no hardware upgrades or workflow changes.
The implementation also brought operational improvements. The platform’s centralized management console gives IT teams real-time visibility into file transfers, synchronization status, and file locking. Engineers can collaborate without delays, and administrators can troubleshoot efficiently with detailed error reporting and proactive alerts.
Employees described the difference in performance as “night and day.” Engineering tools like SolidWorks now operate smoothly across geographies, and the IT team has seen a dramatic drop in file-related support tickets. The software-only approach of Active Everywhere helped Invetech protect previous investments while future-proofing their architecture for global collaboration.
By replacing NetApp Global File Cache with Resilio File Caching, Invetech eliminated sync delays, improved file access speed, and simplified operations. The success of this deployment highlights a growing shift among engineering and hybrid-cloud organizations toward software-defined file caching as a scalable alternative to legacy WAN optimization solutions.
Read the full Invetech case study to learn how they achieved local-speed access, simplified IT operations, and replaced NetApp GFC without changing their infrastructure.
Move Faster Without the Tradeoffs
The point of infrastructure is to get out of the way.
Resilio File Caching removes WAN latency from file operations, eliminates replication complexity, and preserves the centralized data model your governance depends on—all without multiplying storage footprint or introducing consistency headaches.
Your distributed teams get LAN-speed access; your architecture stays simple enough to reason about.
Contact us to see how it works with your environment.
