Dell EMC Isilon
PowerScale (formerly Dell EMC Isilon) is a scale-out network-attached storage (NAS) platform designed for high-performance management of unstructured data, including workloads in media, healthcare, AI, and analytics, with capacities scaling from terabytes to hundreds of petabytes in a single file system.[1] It operates on the OneFS operating system, which integrates file system, volume management, and data protection into a unified software-defined layer running on commodity hardware nodes.[2] Originally developed by Isilon Systems, founded in 2001 in Seattle, Washington, the technology pioneered clustered storage for large-scale file sharing.[3] EMC Corporation acquired Isilon Systems in November 2010 for $2.25 billion to enhance its portfolio in scale-out NAS solutions.[4] Following Dell's acquisition of EMC in 2016, the product line was rebranded as Dell EMC Isilon, emphasizing its role in enterprise data storage.[5] In June 2020, Dell Technologies further rebranded it as PowerScale, introducing enhancements like native S3 object protocol support while maintaining full backward compatibility with existing Isilon clusters.[6] Key capabilities include linear scalability across up to 252 nodes, support for protocols such as NFS, SMB, HDFS, and HTTP, and features like SmartPools for data tiering, FlexProtect for N+4 data protection, and SmartDedupe for efficiency. As of 2025, OneFS continues to evolve with versions supporting advanced AI and security features.[2] The platform enables seamless integration of all-flash, hybrid, and archive nodes, delivering up to 8x performance gains for AI-driven workloads and robust security measures including encryption, auditing, and ransomware detection.[1]Overview
Introduction
Dell EMC Isilon, now rebranded as PowerScale, is a scale-out network-attached storage (NAS) platform designed for high-volume storage, backup, archiving, and analytics of unstructured data such as media files, logs, and sensor data.[1][6] This platform enables organizations to manage massive datasets efficiently, supporting diverse workloads in industries like media, healthcare, and scientific research.[7] The core purpose of PowerScale is to provide scalable file storage that can expand from terabytes to exabytes within a single file system namespace, maintaining consistent performance without degradation as capacity grows.[8] It achieves this through a clustered architecture that allows seamless addition of nodes, ensuring linear scalability for both capacity and throughput.[6] Powered by the OneFS operating system, it unifies storage, networking, and management into a single software layer.[1] Originally developed by Isilon Systems and acquired by EMC in 2010, the platform evolved into Dell EMC Isilon after Dell's 2016 merger with EMC, before being rebranded as PowerScale in 2020 to reflect its expanded capabilities.[6][9] As unstructured data accounts for approximately 80% of all enterprise data and continues to drive the majority of data growth, PowerScale establishes Dell Technologies as a market leader in this domain, recognized by analysts like Gartner for its dominance in distributed file systems.[10][11][12]Key Features
Dell EMC Isilon, now known as PowerScale, offers exceptional scalability through its scale-out architecture, allowing clusters to expand non-disruptively from terabytes to petabytes—or up to 737 PB in high-capacity configurations—within a single file system by simply adding nodes.[1] This design eliminates the need for complex migrations or downtime, enabling seamless growth to meet evolving storage demands.[1] A core feature is the unified namespace, which provides a single, logical view of all file and object data across the cluster, simplifying management and access for petabyte-scale environments.[1] This approach reduces administrative overhead by treating the entire cluster as one cohesive file system, regardless of the underlying hardware diversity. The OneFS operating system underpins this capability, ensuring consistent data visibility and policy application.[13] Isilon delivers high performance via parallel access mechanisms, supporting thousands of concurrent users and connections while achieving up to 15.8 million IOPS per cluster.[6][14] Optimized for demanding workloads like AI/ML, it offers low-latency throughput and up to 8x performance acceleration through advanced processors and caching. As of 2025, enhancements include support for 122TB SSDs in new nodes, enabling higher capacities and AI performance.[1][15] Efficiency is enhanced by inline data reduction techniques, including deduplication and compression, which typically achieve a 3:1 reduction ratio and up to 6x overall efficiency gains, minimizing storage requirements without impacting performance.[16][6] These features, processed in real-time, help reduce power consumption by up to 50% and optimize resource utilization.[1] Backward compatibility ensures seamless integration, as new PowerScale nodes can be added directly to existing Isilon clusters without disruption, providing a straightforward upgrade path for legacy deployments.[1]History
Founding and Early Years
Isilon Systems was founded in 2001 by Sujal Patel and Paul Mikesell in Seattle, Washington, with the goal of overcoming the scalability limitations of traditional network-attached storage (NAS) systems through innovative scale-out clustered architecture.[17][18] The founders, drawing from their experience in distributed systems, aimed to create a solution that could handle the growing volumes of unstructured data, particularly in industries dealing with large file sets. Development of the OneFS operating system, which would power their products, began during this early period to enable a unified file system across multiple nodes.[19] The company's first product, the Isilon IQ series, was launched in 2003 as the pioneering clustered NAS platform featuring a single distributed file system.[20] This innovation allowed for seamless scaling by adding nodes without the complexity of managing multiple file systems, addressing key pain points in traditional storage. Initially targeted at media and entertainment sectors facing petabyte-scale data challenges, such as digital content archiving and post-production workflows, the IQ series supported essential protocols including NFS and SMB/CIFS to facilitate broad adoption.[21][22] By 2004, Isilon had secured nearly $30 million in total funding across multiple rounds, including a $15.5 million Series C led by Lehman Brothers, enabling rapid product development and market expansion.[23][24] The company achieved significant growth, with revenues increasing from $1.2 million in 2003 to $6.8 million in 2004, driven by deployments in high-data-volume environments. This momentum culminated in an initial public offering (IPO) on December 15, 2006, where Isilon raised $108.6 million by selling 8.35 million shares at $13 each, resulting in a market valuation exceeding $1.4 billion at the close of trading.[25][26][3]Acquisition by EMC
On November 15, 2010, EMC Corporation announced its agreement to acquire Isilon Systems, Inc., for approximately $2.25 billion in cash, or $33.85 per share, representing a 29% premium over Isilon's closing stock price at the time.[4][27] The tender offer was completed on December 20, 2010, with the full acquisition finalized the following day after receiving sufficient shareholder tender and regulatory clearances, allowing EMC to merge Isilon into its operations.[28][29] EMC's primary motivations for the acquisition centered on enhancing its scale-out network-attached storage (NAS) capabilities to address the emerging demands of big data analytics and unstructured data management. At the time, EMC's portfolio was heavily oriented toward block-based storage solutions like its Symmetrix and Clariion systems, but it lacked robust offerings in the rapidly growing file-based, scale-out NAS market where Isilon excelled. By integrating Isilon's clustered storage technology with EMC's Atmos cloud storage platform, the deal aimed to create a comprehensive, low-cost infrastructure capable of handling petabyte-scale data volumes for enterprises entering the big data era.[4][30][31] Following the acquisition, Isilon operated as a semi-autonomous division within EMC's Information Infrastructure business unit, preserving its Seattle headquarters and retaining its core engineering team to continue developing the OneFS operating system independently. This structure allowed Isilon to maintain its innovative momentum while benefiting from EMC's global sales channels, R&D resources, and customer base, fostering collaborative advancements in scale-out storage without immediate full assimilation.[32][33] Under EMC's ownership, Isilon experienced accelerated growth, with quarterly revenues more than doubling year-over-year in the first full quarter post-acquisition and continuing strong performance into 2011 and beyond, as it expanded deeper into enterprise data centers and cloud-integrated solutions. A notable milestone came in May 2011, when EMC Isilon unveiled the IQ 108NL node, enabling the world's largest single file system at over 15 petabytes in a unified namespace, underscoring the combined entity's leadership in massive-scale storage deployments for media, scientific, and analytics workloads.[34][35][36]Dell Merger and Rebranding
In September 2016, Dell Technologies completed its $67 billion acquisition of EMC Corporation, the largest technology merger at the time, which integrated EMC's portfolio—including Isilon—into a unified entity focused on enterprise infrastructure solutions.[37] Following the merger, Isilon was rebranded as Dell EMC Isilon to align with Dell's emerging storage lineup, enabling seamless incorporation into broader hybrid cloud environments and edge computing strategies.[38] This integration drove operational enhancements, such as expanded research and development efforts targeting AI-driven workloads, while bolstering Isilon's role in Dell's comprehensive data management ecosystem for hybrid and multi-cloud deployments.[38] In June 2020, Dell Technologies further unified its storage branding by rebranding Dell EMC Isilon to PowerScale, a move that standardized nomenclature across its scale-out NAS offerings without disrupting existing deployments, as the OneFS operating system ensured full backward compatibility with prior Isilon hardware.[6][39] By 2025, PowerScale had evolved with the release of OneFS version 9.12 in August, introducing features like multi-party authorization to support secure, large-scale data operations, and serving over 16,000 global customers through its emphasis on AI data platforms.[40][1] The strategic pivot toward unstructured data management for AI applications was underscored in 2021 with the introduction of GPU-accelerated nodes, such as the F900 series integrated with NVIDIA GPUDirect Storage, enabling direct data transfer to GPUs for high-performance AI training and inference.[8][41]Technology and Architecture
OneFS Operating System
OneFS is a proprietary distributed operating system developed by Isilon Systems, serving as the core software layer for Dell EMC Isilon (now PowerScale) scale-out NAS storage systems. First released in 2003, it integrates the three traditional layers of storage architecture—the file system, volume manager, and data protection—into a single unified software layer that spans all nodes in a cluster. This one-layer approach eliminates the complexity of separate components, enabling a single file system and namespace that scales seamlessly from tens of terabytes to hundreds of petabytes without downtime or reconfiguration. By distributing both data and metadata evenly across nodes, OneFS simplifies administration and supports clusters of up to 252 nodes.[42][2] At its foundation, OneFS features a single extensible file system module that stripes data across all nodes in fixed-size blocks, similar to XFS in extensibility but designed for clustered, parallel access. This striping mechanism ensures that I/O operations are distributed symmetrically, allowing multiple clients to read and write to the same file concurrently for enhanced throughput and low latency. The protection module employs Reed-Solomon erasure coding for efficient data redundancy, replacing conventional RAID with flexible schemes like N+2 parity, where data is protected against multiple drive or node failures while optimizing space usage. For instance, an 8+2 configuration uses 8 data stripe units and 2 parity units to tolerate up to two node failures, delivering approximately 80% storage efficiency (calculated as usable capacity over total raw capacity: \frac{8}{10} = 0.8). The management module automates cluster operations, including data rebalancing, protection verification via FlexProtect jobs, and policy enforcement, reducing administrative overhead.[43][2][44] OneFS has evolved to support key enterprise protocols, including SMB 3.0 for Windows environments, NFSv4.1 for UNIX/Linux access, and HTTP for web-based content serving. It also integrates natively with Hadoop via HDFS for big data analytics and provides S3-compatible object storage APIs, enabling hybrid workflows that blend file and object access. These capabilities allow OneFS to handle diverse applications, from high-performance computing to media processing, without requiring separate silos.[2][43] Performance in OneFS is driven by its parallel I/O architecture, where data access leverages the aggregate resources of all nodes, enabling linear scalability in throughput and IOPS as the cluster grows. Large configurations can achieve up to 945 GB/s aggregate throughput, supporting intensive workloads like AI training and video rendering with minimal bottlenecks. This is facilitated by features such as SmartRead prefetching and a globally coherent cache of up to 181 TB, ensuring efficient handling of sequential and random I/O patterns.[43][45]Scale-Out NAS Design
The Dell EMC Isilon scale-out NAS architecture is built around a clustered design where multiple nodes interconnect to form a single, unified storage fabric, eliminating single points of failure through distributed processing and redundant pathways. Nodes communicate internally via high-speed Ethernet (supporting 10, 40, or 100 GbE) or InfiniBand backends, creating a resilient mesh network that handles all intra-cluster traffic, including data striping and metadata operations. This interconnected fabric enables seamless parallel access and load balancing across the cluster, ensuring high availability without dedicated controllers or specialized hardware.[46] Scalability in Isilon follows a linear model, where administrators can add nodes non-disruptively to expand both capacity and performance proportionally, supporting clusters of up to 252 nodes and up to 720 PB of raw capacity. As of 2025, PowerScale supports drives up to 122 TB, enabling even higher capacities. This approach allows organizations to start small and grow as data needs evolve, with the OneFS operating system managing resource distribution to maintain efficiency. For instance, adding nodes increases aggregate throughput and IOPS without reconfiguring the file system, providing predictable scaling for large-scale unstructured data environments.[47][43][48] A core element of the design is the single global namespace, which presents all data across the cluster as one cohesive file system, simplifying management and access regardless of physical node distribution. OneFS employs a distributed lock manager to coordinate concurrent file access and modifications, ensuring data consistency through coordinated locking mechanisms across all nodes. This unified view supports multi-protocol front-end access, including NFS, SMB, HTTP, and HDFS, allowing diverse clients to interact with the same dataset without silos or complex mappings.[49] Networking in the Isilon architecture separates front-end client connections from the backend cluster fabric, with Ethernet or InfiniBand providing low-latency, high-bandwidth interconnects for internal operations. Front-end protocols enable multi-protocol support over standard Ethernet, while the backend ensures fault-tolerant communication for all cluster-wide tasks. This dual-network model optimizes performance by isolating client I/O from internal synchronization, supporting speeds up to 100 GbE for both.[46] Efficiency is enhanced through SmartPools, a policy-based tiering feature that automatically migrates data across heterogeneous node types—such as all-flash, hybrid, and archive—within the single namespace, avoiding traditional storage silos. Administrators define file pool policies based on attributes like age, size, or access patterns to place hot data on performance tiers and cold data on capacity-optimized ones, achieving up to 80% storage utilization. This dynamic tiering operates via the OneFS Job Engine, minimizing disruption while optimizing costs and performance for mixed workloads.[50]Data Protection Mechanisms
Dell EMC Isilon, now known as Dell PowerScale, incorporates robust data protection mechanisms within its OneFS operating system to ensure high availability and resilience against failures, leveraging software-defined approaches for redundancy and recovery. These features are integrated through the OneFS protection module, which handles parity calculations, replication, and security at the file system level.[43] Erasure coding in OneFS employs a software-defined parity scheme using an N+M configuration, where N represents the number of data stripes and M the number of protection stripes, enabling tolerance of up to M simultaneous node or drive failures. This approach distributes data and parity across the cluster, allowing reconstruction from any N surviving stripes. Administrators can configure M from 2 to 6 or higher depending on the protection level, such as +2n or +4n, balancing redundancy against storage efficiency. The usable capacity efficiency is calculated as \frac{N}{N+M} of the total raw capacity, providing scalable protection without dedicated hardware RAID controllers.[51][43] OneFS implements erasure coding via the Reed-Solomon algorithm, a forward error correction method that generates parity information mathematically to recover lost data blocks. For a 4+2 configuration, 4 data blocks are combined with 2 parity blocks derived from finite field arithmetic over Galois fields, allowing reconstruction if up to 2 blocks fail; the parity is computed as p_1 = \sum (d_i \cdot \alpha^i) and p_2 = \sum (d_i \cdot \alpha^{2i}), where d_i are data symbols and \alpha is a primitive element. Similarly, a 6+2 setup uses 6 data blocks and 2 parity blocks, supporting the same failure tolerance with higher efficiency. These configurations achieve space efficiencies of 67% for 4+2 and 75% for 6+2, offering up to 80% or more usable capacity compared to traditional RAID6 in larger clusters, due to wider stripes and parallel processing that reduce overhead.[51][43] SnapshotIQ enables point-in-time, read-only snapshots at the directory level, created in under 1 second with support for up to 1,024 per directory, using copy-on-write or redirect-on-write strategies to minimize overhead. For immutability, SmartLock provides Write Once Read Many (WORM) functionality on these snapshots in enterprise or compliance modes, enforcing retention policies to prevent alterations or deletions. SyncIQ facilitates asynchronous replication across clusters for disaster recovery, supporting up to 1,000 policies with incremental transfers, bandwidth throttling, and TLS encryption for data in transit.[52][51] Security features include AES-256 encryption for data at rest, implemented via self-encrypting drives or software, alongside multi-factor authentication and role-based access controls. The PowerScale Cybersecurity Suite enhances protection with real-time ransomware detection through behavioral analytics and audit logging via the Common Event Enabler framework, enabling isolation and automated alerts for suspicious activities.[53][52][51] Recovery processes leverage self-healing mechanisms, where file system integrity checks and repairs occur in the background via the FlexProtect job engine, completing in minutes even for multi-node failures through parallel reconstruction across the cluster. Cluster expansions add nodes without downtime, as OneFS dynamically redistributes data and protection in real-time using virtual hot spares. SnapRevert allows near-instantaneous restoration from snapshots, while SyncIQ supports push-button failover and failback for replicated data.[43][51]Products
Hardware Nodes
Dell PowerScale hardware nodes, formerly known as Isilon nodes, form the foundational building blocks of scale-out NAS clusters, offering a range of series tailored to different performance and capacity needs. The F-series consists of all-flash nodes designed for high-performance workloads such as AI and media processing. For instance, the F910 model provides raw capacity scaling from 92 TB to 737 TB per node using NVMe SSDs, making it suitable for demanding applications requiring low latency and high throughput.[54][55] The H-series features hybrid nodes that balance performance and cost for general enterprise file storage. The H700, for example, supports chassis capacities from 120 TB to 1.4 PB, with configurations including up to 60 HDDs and SSD caching per chassis (15 drives per node across four nodes). These nodes target mixed workloads where capacity efficiency is key alongside moderate performance demands.[56][57] The A-series comprises archive nodes optimized for low-cost, high-capacity cold storage. The A300 model offers similar chassis capacities of 120 TB to 1.4 PB, emphasizing energy-efficient designs for infrequently accessed data with up to 60 HDDs per chassis. This series prioritizes density and cost per terabyte for long-term retention.[58][59] All PowerScale nodes are powered by Intel Xeon Scalable processors, enabling robust compute capabilities across series. Drive options include HDDs up to 24 TB and SSDs up to 30.72 TB, with NVMe support primarily in F-series for enhanced I/O performance. The OneFS operating system optimizes node performance by distributing data and workloads evenly across the cluster.[54] Node evolution traces back to the original Isilon IQ series introduced in 2003, progressing to advanced models like the all-flash F800 in 2017 with up to 924 TB per node, and the hybrid H5600 in 2019 for deeper chassis integration. Current generations maintain backward compatibility, allowing all node types to interoperate seamlessly in mixed clusters up to a maximum of 252 nodes.[60][47][61] Form factors vary by series: F-series nodes use compact 2U chassis housing up to 24 drives per node, while H- and A-series employ 4U chassis accommodating four nodes with up to 20 drives per node in higher-density models like the H7100. Power consumption and cooling are optimized for rack density, supporting efficient data center deployments.[62][63]| Series | Type | Example Model | Capacity Range (Raw, per Node) | Target Use | Chassis/Form | Max Drives/Node |
|---|---|---|---|---|---|---|
| F-series | All-Flash | F910 | 92 TB - 737 TB | High-performance AI/media | 2U | 24 (NVMe SSD) |
| H-series | Hybrid | H700 | 30 TB - 360 TB | Enterprise files | 4U (4 nodes/chassis) | 15-20 (HDD + SSD cache) |
| A-series | Archive | A300 | 30 TB - 360 TB | Cold storage | 4U (4 nodes/chassis) | 15 (HDD) |