The UnAppliance provides Higher Performance, Lower Cost File Serving

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1 The UnAppliance provides Higher Performance, Lower Cost File Serving The UnAppliance is an alternative to traditional NAS solutions using industry standard servers and storage for a more efficient and manageable data center. File serving over Ethernet networks using network-attached storage (NAS) appliances or UNIX file servers is ubiquitous in today s data center. However, as its usage has grown, IT organizations have faced multiple challenges: The PolyServe File Serving solution delivers price, performance and flexibility advantages significantly beyond that of today s standard NAS filers, based on traditional file systems. Arun Taneja Consulting Analyst Manageability. Ever-larger numbers of clients have driven many IT organizations to deploy multiple UNIX servers or NAS appliances, introducing management complexity and overhead in maintaining redundant copies of data. Scalability. Some users have turned to very high-end servers and NAS appliances to simplify the provisioning of file services to a large number of clients or to support heavy workloads. However, this comes at a steep cost and, in many cases, this high-end hardware cannot deliver desired IO performance. Availability. When NAS appliances are installed in pairs to provide high availability, the cost doubles, and still there is a lot of unnecessary downtime for maintenance and upgrades. Fit with Existing Infrastructure. NAS appliances come with their own proprietary hardware, software and management tools, adding yet more complexity to the datacenter and another set of processes of IT to learn. Cost Reduction. IT departments are being challenged to reduce operating expenses. The proliferation of file serving appliances has drastically increased operating expenses, and provides low hanging fruit for significant expense reduction. PAGE 1 of 13 (877)

2 What is needed is a way to provide scalable, highly available file services using inexpensive, industry-standard servers that can be added incrementally as demands require, all while retaining the management simplicity of a single server and a single pool of exported file systems. What is needed is the UnAppliance. PolyServe s File Serving software solution is the UnAppliance. PolyServe enables huge gains in data center efficiency and cost savings by delivering the next generation file serving architecture. This architecture provides benefits such as: 6:1 price/performance advantage over traditional NAS Shared data cluster for improved management and resource utilization Use of industry-standard servers and storage for choice and cost savings Pay-as-you-grow scaling of file services Five times the performance of traditional NAS appliances Industry leading Fault Tolerance at no additional cost This whitepaper on file serving for Linux environments will detail how PolyServe s UnAppliance File Serving solution can deliver these benefits and provide incredible Total Cost of Ownership (TCO) savings to data center operations. The Economics of File Serving Clusters PolyServe s File Serving solution represents a different approach to shared storage compared to the traditional, fully integrated server, storage and software appliances provided by vendors such as EMC and Network Appliance. The price of industry standard storage has dropped drastically over the last decade. Yet traditional NAS appliances do not allow the end customer to take advantage of the drop in storage costs. Their integrated approach and proprietary software locks the customer into their solution, alleviating any choice for standard storage or management and backup applications. As these appliances proliferate across the enterprise, often referred to as appliance sprawl, each one has to be managed as a separate entity and each one still is an isolated silo of data. In short, the appliances work fine for a single point solution, but do not scale well from an operations management perspective. I/O performance does not improve each additional appliance purchased. Managing routine backup or balancing users or applications across file systems is still performed on each individual unit. The PolyServe File Serving solution, however, takes advantage of the volume economics of industry standard storage, servers and software. PolyServe is file serving cluster software that when combined with industry-standard servers and storage and an enterprise Linux operating system enables a 6:1 price/performance advantage compared to traditional NAS. PolyServe enables scalable network file serving built on shared data such that every server and application can have access to the same pool of shared storage. This enables great economies of scale for performance and manageability. And with PolyServe software, IT departments can use their preferred choice for network management applications, backup software, anti-virus software and other common applications. PAGE 2 of 13 (877)

3 The following table provides an example of the price-performance difference between the PolyServe File Serving solution and traditional NAS appliances. Traditionally, the most popular way to achieve highly available NAS is to deploy a cluster of two independent NAS filers linked together for failover. Based on PolyServe customer benchmarks, a representative enterpriseclass NAS failover cluster can deliver approximately 250 megabytes per second (MB/second) of highly available throughput performance (based on sustained sequential writes to a single file system). The list price of a representative enterprise-class NAS failover cluster consisting of two NAS filers, 12.6 terabytes (TB) of storage and licenses for the NFS protocol and failover clustering software would be $476,000 1 Hardware Software Storage Table 1. Price and Performance Comparison Between a NAS Failover Cluster and a Two-node PolyServe File Serving Cluster Price-Performance ($ per MB/s) Price per TB Enterprise-Class NAS Failover Cluster 2 NAS Filers Clustered Failover Option NFS Option 12.6 TB $1,904 $37, NAS Cluster Solution 2 Industry Standard Servers (2 CPU, 2GB Memory) PolyServe NAS Cluster Software Linux OS (Includes NFS, CIFS, HTTP, and FTP) 12.6 TB Price ($) 1 $476,000 $79,242 Throughput (MB/s) MB/s 250 MB/s $ $6, A two-node PolyServe File Serving cluster provides equivalent performance, but only costs $79, The PolyServe File Serving solution also allows for the linear scaling of data throughput as servers are added to the cluster, achieving multiple gigabytes per second throughput in a cluster of up to 16 nodes further increasing PolyServe s price/performance advantage. In short, the PolyServe File Serving solution delivers the following benefits over a comparable enterprise NAS appliance solution: 82% less expensive in total solution cost 82% more price performance as measured by price per MB/s 82% less expensive in terms of price per TB 1 Source: Taneja Group 2 Source: list pricing information on vendor Web sites as of March 17, 2004 PAGE 3 of 13 (877)

4 Introducing File Serving Clusters The PolyServe File Serving solution is software that allows a customer to leverage the volume economics of industry-standard servers and storage and couple those components into a single high-performance file serving system. At its core, the PolyServe File Serving solution integrates Network File System (NFS) functionality or Common Internet File System (CIFS) protocol with a true symmetric cluster file system, high-availability services and cluster and storage management capabilities. The product aggregates up to 16 low-cost Linux-based servers for high-performance, fault-tolerant file serving across a SAN. Shared data and management capabilities ease IT administration by enabling servers and storage to be managed as one. At the heart of the solution is PolyServe Matrix Server, the shared data clustering software that allows the performance of multiple cost-effective servers to be aggregated together. PolyServe Matrix Server and x86-based servers running Linux change the economics of NAS deployment. A cluster of inexpensive servers can now function as a single, easily managed, incrementally scalable ( pay as you grow ), highly available NAS appliance, solving the problems posed by conventional approaches: Manageability. The cluster can be treated as a single NAS server with a single pool of storage and a single set of exported file systems. There is no need to create redundant copies of data, or to divide clients manually among different servers. Backup can be performed on a single pool of data, not multiple backup tasks on each individual appliance. Scalability. Additional servers and storage can be added to the cluster to meet growing workloads. Additional servers and storage can be added on-the-fly without disrupting the file serving application. And performance scales linearly beyond 2 GB/s. Availability. In the event of failure, servers in the cluster automatically take over each others clients immediately, with no interruption of service. Dynamic on-line addition of servers and storage means that no scheduled downtime is required for capacity upgrades. Cost Reduction. By using industry standard servers and storage, the price of the overall solution is 20% that of NAS appliances. Removing subscription fees for the hardware and the required backup, anti-virus and management applications of proprietary NAS solutions provides significant annual operational cost reduction. PolyServe Matrix Server Technology PolyServe Matrix Server is shared data clustering software that incorporates several key technologies: A high-performance, symmetric cluster file system. With Matrix Server, a cluster of industry-standard servers can share concurrent read/write access to file systems resident in a SAN, as shown in Figure 1. Matrix Server provides very high throughput PAGE 4 of 13 (877)

5 for even the most demanding workloads, with direct disk access speeds and complete cache consistency among servers in the cluster.* High-availability infrastructure. Matrix Server protects against server, network and storage interconnect failures. It provides automatic restart of servers and services, immediate failover of clients to surviving nodes and support for Multi-Path I/O (MPIO). Cluster Volume Manager. With PolyServe s CVM, multiple storage arrays can be clustered for improved performance and scalability. Storage can be added on the fly, and virtually any mix of storage vendor and type can be used in the cluster. Integrated cluster-wide management. The management infrastructure enables a single console to provide an overview of server status. Cluster operations can be reconfigured either from the console or using a command line tool, from any member of the cluster. Figure 1. With PolyServe File Serving solution, all servers in the cluster have direct, simultaneous access to file systems in the SAN. These characteristics make the File Serving solution powered by PolyServe Matrix Server an excellent platform for delivering highly scalable, highly available NAS, as depicted in Figure 2. Here, a cluster of industry-standard servers running the PolyServe File Serving software solution share access to a common set of file systems that they export via NFS to clients. A client can access the exported file systems via any of the servers in the cluster. Also, multiple clients that have mounted the file systems via different servers can use the same files simultaneously, receiving the same results as if they were using a single server. Thus, clients can be spread among servers using DNS round robin. (Alternately, a hardware load balancer can be used.) PolyServe s Cluster Volume Manager (CVM) enables superior storage management and higher performance from storage. PolyServe s CVM enables storage volumes to span * Because of these characteristics, Matrix Server can support applications running on cluster members that require better latency, write performance, or cache consistency than NFS can deliver, such as very large databases and large-scale custom data processing. These applications are described in other PolyServe Solution Briefs at PAGE 5 of 13 (877)

6 multiple arrays and stripe data across multiple LUNs or arrays for optimum performance. By consolidating various isolated arrays of storage into a shared storage pool, utilization rates can go from an industry average of about 50% up to 80%. Striping across arrays aggregates the I/O performance of individual arrays, thereby alleviating a possible performance bottleneck created by a single array. Figure 2. All servers export the same set of file systems. Matrix Server s high-availability features, along with the specific support for NFS or CIFS failover provided by the File Serving solution, ensure that in the event of a failure, clients will transparently be moved to a surviving cluster node. Thus, the cluster as a whole acts as a single, highly scalable, highly available virtual NFS server, but one made out of industrystandard components with unbeatable price/performance. The Challenge of Scaling and Managing NAS As the capacity of NAS appliances or UNIX NFS servers is exceeded for particular applications, customers have traditionally been forced to choose between either upgrading to larger file servers or NAS appliances or adding more of them, perhaps replicating the same data among them. These choices have serious drawbacks: Larger servers and NAS appliances are more expensive per increment of serving capacity, and in some cases still remain bottlenecks on overall performance. More servers create additional points of server and storage management. NAS appliances contain proprietary hardware and operating systems, requiring additional and proprietary administrative applications. Adding additional OSes, management software, data protection and security software only complicates IT managers jobs. Fragmentation of workloads across more servers and storage decreases capacity utilization. PAGE 6 of 13 (877)

7 Replicated data wastes storage capacity on copies of data and generates new data management challenges associated with keeping data copies consistent. High availability becomes increasingly expensive, requiring duplication of large amounts of expensive hardware. PolyServe File Serving solution running on industry-standard servers addresses all of these problems. PolyServe File Serving Cluster is the UnAppliance Cost-Effective Scalability A UNIX NFS server or NAS appliance represents a potential performance bottleneck for mission-critical, data-intensive applications. In NFS, file system operations performed by clients generate network requests that must be received by the server, interpreted, executed by the server on the client s behalf often requiring disk I/O and then replied to. Thus, a large number of NFS clients, or even a small number of clients with heavy demands, can saturate the NFS server s network interfaces, CPU or storage connections, causing performance to degrade to an unacceptable level. These NFS performance and scalability issues are particularly acute in oil and gas, biosciences, video production, and credit card data processing applications where there is a need to process many single files in parallel or large data sets in sequence. Figure 3. NAS Configuration vs. Matrix Configuration. In a high-performance PolyServe File Serving, each individual server contributes incremental resources to the cluster: Network bandwidth for client requests and replies, CPU capacity for file system processing and I/O bandwidth to storage. No individual server s capacity in any of these dimensions imposes a bottleneck on system performance. As needs grow, a cluster can be scaled from as little as a pair of dual-processor servers to a set of 16 servers each with four or eight CPUs, multiple gigabit Ethernet and Fibre Channel connections all without interrupting client service and without requiring any migration of data. PAGE 7 of 13 (877)

8 Similarly, storage can be scaled to meet user demand, with application disruption and without lock-in to any certain vendor. Reduce initial capital expenditures by right-sizing the initial deployment no need to over-provision for headroom years down the road. Add storage capacity when needed, by either adding devices to an array or by adding additional arrays. This is true on-demand scalability and another reason why PolyServe is the UnAppliance. MegaBytes per Second (MB/s) PolyServe NAS I/O Throughput (via NFS) 1,200 1, , , Cluster Size (Nodes) Figure 4. PolyServe File Serving Performance In a recent benchmark, PolyServe demonstrated that a nine-node cluster could deliver over one GigaByte per second of I/O throughput. In fact, based on the findings of that benchmark, a 10-node PolyServe File Serving cluster showed performance 470% faster than a traditional NAS filer. Unlike some cluster file systems that rely on a master node to schedule IO traffic or maintain metadata, Matrix Server is implemented with a completely symmetric architecture in which there is no bottleneck master node. In a Matrix Server cluster, each cluster member is equally able to perform all file system operations on behalf of its clients, and every incremental server added to the cluster enhances the bandwidth available to clients. PAGE 8 of 13 (877)

9 PolyServe NAS Scalability (via NFS) Scaling Coefficient 110% 100% 90% 80% 70% 60% 50% Cluster Size (Nodes) Figure 5. The Near Linear Scalability of PolyServe File Serving Performance As demonstrated by the data in Figure 5, the PolyServe File Serving cluster exhibits near linear scaling. In fact, the PolyServe solution doubled performance with a doubling of the cluster size (100% scalability completely linear) up to eight nodes. With cluster sizes in excess of eight nodes, PolyServe File Serving demonstrated scaling of 98% meaning each incremental node resulted in 98% increase in performance of the first node in the cluster. This data demonstrates that a PolyServe File Serving allows customers to pay as they grow and get the most bang for their buck by using industry-standard hardware. Because a PolyServe File Serving cluster can be built out of the most cost-effective industry-standard servers and storage, scalability comes at a very attractive price point when compared to traditional, high-end UNIX NFS servers or NAS appliances. Leverage Existing Resources As NAS appliances bring proprietary hardware and operating systems into the data center, a new set of management software, data protection and security software, business processes and IT training is required. This adds complexity and increased management workloads to the IT staff in an era where solutions should be providing greater simplicity and improved systems management. PolyServe s File Serving solution simplifies the data center by leveraging server hardware, storage hardware, networking infrastructure, operating systems and applications already in the datacenter. PolyServe File Serving solution for Linux runs on industry standard servers and storage and is compatible with popular system management software and data protection and security applications that are already in use in most data centers. This saves money in not having to purchase new licenses for additional software, and time in not having to train IT staff on new applications and hardware support. PAGE 9 of 13 (877)

10 Improved Manageability Traditionally, multiple NAS filers or UNIX NFS servers have required administrators to divide data and clients among them, perhaps replicate data among servers and monitor and provision free space separately on each server or filer. In a PolyServe File Serving environment, none of this is required: All servers in the cluster can export a single set of file systems simultaneously, there is, therefore, no need to divide data among separate servers, or to replicate data among servers. Similarly, since any server can service any client s requests, there is no need to assign clients manually to individual servers. Clients can be balanced among servers automatically using DNS round robin or a hardware load-balancer. In either case, no manual intervention is required. Free space is shared among all servers, simplifying storage provisioning and optimizing resource utilization. The shared data architecture of PolyServe means that all data can be backed up at once, by any server in the cluster. Applications don t have to be put on hold and valuable CPU resources aren t hijacked for backup operations. PolyServe s management consoles make managing the cluster easy. Inherent High Availability Matrix Server includes built-in high availability functionality that permits the cluster to detect and respond to failures of network interfaces, storage interfaces, servers and operating systems within the cluster. The PolyServe File Serving solution builds on this infrastructure to provide transparent failover of NFS sessions. A single server can provide failover protection for the entire cluster. If a server fails, Matrix Server will automatically reassign the failed server s IP address to the standby server, allowing affected clients to continue making NFS requests without any interruption of service. In fact, typically a client will have no indication that a server failure has occurred. Because a single machine can provide failover protection for the entire cluster, it is not necessary to buy hardware in pairs to achieve high-availability. For example, in Figure 3, one server could provide fail-over protection for the other nine, giving just a 10% overhead for availability, as opposed to 50% in a typical, paired configuration. Conversely, any server can provide failover for any other server. Such that if more than one server dies, other servers can pick up the load and redistribute the traffic over all servers. In addition to protecting clients from failures, Matrix Server also enhances availability by reducing the need for scheduled downtime. Online addition of servers and storage is supported, making it possible to grow from, say, a three-node cluster supporting just a few hundred gigabytes of storage to a 10-node cluster hosting many terabytes, with no interruption of service for system upgrades, and with no need to reconfigure or restart any clients. PAGE 10 of 13 (877)

11 PolyServe File Serving Features and Benefits The following table summarizes the capabilities of the PolyServe File Serving solution. Table 2 - Features and Benefits of PolyServe File Serving powered by Matrix Server Feature Support for NFS, CIFS, FTP, and HTTP protocols Symmetrical Cluster File System with Distributed Lock and Metadata Management Cluster Volume Manager (CVM) Online Storage Capacity Growth Large File Systems Support Cache Coherency Across All Nodes Transparent Failover for NFS/CIFS Client and Session State through Matrix Server File Serving Option Single Cluster-wide NFS or CIFS Mount Point Single Pools of Storage Benefit The PolyServe File Serving supports all standard file access and sharing protocols, like NFS, CIFS, FTP, and HTPP without requiring additional licensing costs. Scalability. Each additional server in a cluster adds more aggregate I/O throughput. Due to PolyServe s unique architecture, Matrix Server can deliver near linear scalability of aggregate I/O throughput (as measured by NFS/CIFS operations per second) as additional servers are added to the cluster. Choice, Scalability & Performance. The ability to stripe data across LUNs and across storage arrays enables higher performance on less expensive storage. Multiple storage types and vendors are supported in a cluster, providing choice of preferred vendor and ability to choose the right storage for the application. Stripe LUNs internal to a storage array or stripe across multiple storage arrays. Storage Scalability and Flexibility. Group LUNs together to create volumes of any size, then grow volumes as needed, without disrupting the application. Online capacity growth ensures high utilization of storage; right-size your storage needs today, then easily increase storage capacity when needed. Large data store support, large volume sizes. Group multiple 2 TB LUNs together to build file systems up to 16 TB for applications with very high capacity needs. With 512 file systems supported in a cluster, it is possible to build clusters of 8 Petabytes. Scalability and Manageability. Cache coherency means that clients can connect to any of the servers in the cluster and receive exactly the same responses to NFS/CIFS requests. This provides simple scalability by removing the need to divide clients manually among servers. Availability. Higher system availability and minimized downtime. Includes integrated clusterware that monitors the health of the network, server hardware, and NFS/CIFS services. Initiates failover to migrate a NFS/CIFS client from a failed server to a healthy server. The NFS/CIFS client is unaware that a failure has occurred, nor does it need to remount the NFS/CIFS mountpoint. Server Capacity Utilization. Ensures even distribution of NFS/CIFS client load across the cluster. Upon mounting an NFS/CIFS file system, NFS/CIFS clients are associated with a particular server via round robin scheduling. Once they mount to a particular server, their NFS/CIFS mount persists with that server for the duration. Single point of management for backup and provisioning. Storage across the cluster is managed as a single pool. An administrator can PAGE 11 of 13 (877)

12 Feature Storage Area Network with Consolidated Data Ability to Use Industry- Standard Servers and Storage Rather than Large UNIX Servers or NAS Filers Reduced Cost for High Availability Centralized Cluster-wide Administration with GUI and Command Line Interface Online Addition of Servers and Storage Benefit backup all the data from a single node and can provision storage without any disruption in service. Data Capacity Utilization and Storage Management Efficiency. Centralization of data makes storage management more effective and increases storage utilization rates. Lower Total Cost of Server Capacity. Ownership (TCO) and compelling price per performance (measured by $/nfs or $/cfs operations). The ability to use industry-standard servers, storage and Linux operating system delivers lower hardware, software and maintenance cost. PolyServe delivers a 6-to-1 price/performance advantage over UNIX file servers and NAS appliances. Lower Cost of Providing Availability. Because a cluster is composed of many smaller servers rather than one large server, and because the cost of buying a smaller server is significantly less expensive per increment of processing power, the cost of providing failover capacity is much lower. Additionally, since Matrix Server supports many-to-one failover capabilities, there is no need to maintain a spare server for every server that requires high-availability services. Lower Systems Management Cost. Reduces the complexity of administering a cluster of NFS/CIFS servers. Cluster and file system configurations can be changed from a central point. Lower Ongoing Cost of Capacity/ Pay as You Grow. No need to over-provision to avoid fork-lift upgrades. Grow cluster and storage as business dictates without having to provision hardware to forecasted peak load. Ride the curves that cause each increment of compute capacity and each megabyte of storage to get less expensive every six months. Summary The PolyServe File Serving solution powered by PolyServe Matrix Server provides a unique solution that addresses the scalability, availability and manageability of file serving in the enterprise. PolyServe s File Serving solution addresses the scalability and performance bottleneck posed by the most demanding, data-intensive applications. In addition, the PolyServe File Serving can be utilized to consolidate numerous, disparate NAS filers or NFS servers onto a single centrally managed file serving that provides inherent high availability and a clear growth path. By leveraging industry standard hardware and software for a high performance, fault tolerant file serving solution, PolyServe is the UnAppliance. PAGE 12 of 13 (877)

13 PolyServe, Inc. (877) (within U.S.) NW Amberwood Drive (503) (fax) Suite 150 (503) (outside U.S.) Beaverton, OR Copyright 2005 by PolyServe, Inc. All rights reserved. PolyServe and the PolyServe logo are trademarks of PolyServe, Inc. All other trademarks mentioned in this document are the property of their respective owners. This document is for informational purposes only and does not set forth any warranty, expressed or implied, concerning any software, software feature, or service offered or to be offered by PolyServe, Inc. PolyServe, Inc., reserves the right to make changes to this document at any time, without notice, and assumes no responsibility for its use. This informational document describes features that may not be currently available. Contact PolyServe corporate headquarters for information on feature and product availability. The PolyServe Matrix Server product uses software developed by Spread Concepts LLC for use in the Spread toolkit. For more information about Spread, see Linux File Serving WP v7.doc PAGE 13 of 13 (877)