by Steve Rogers Director of Technical Marketing i Unified Network Storage Increases the Cost-effectiveness of the Distributed Information Value Chain The pervasive global economy is driving the continued and exponential growth of enterprise data. The demand for high-speed access to data, generated by e-commerce, email, various enterprise productivity applications, as well as Web serving and digitized media and information is insatiable at all levels of the enterprise. Companies are under tremendous pressure to store, protect, distribute, and derive value from all that data. Thus, assessing and understanding the Information Value Chain storing the right data on the right storage distributed throughout an enterprise has become one of the most pressing issues facing Chief Information Officers today. page 1 Storage Today Today's storage technology market offers two broad options for storing data: direct attached storage (DAS) and networked storage, which consists of storage area networks (SANs) and network attached storage (NAS). While DAS has dominated the storage market in the past, according to IDC, 60 percent of external disk storage being purchased today is networked storage, and analysts expect it to grow significantly over the next few years. Networked storage architectures, separating servers from their storage, offer flexible, scalable capacities and offload some of the provisioning and management tasks from the server. To understand the ongoing shift from DAS to networked storage, it is necessary to first discuss the different architectures in more detail. Direct Attached Storage In its simplest form, direct attached storage (DAS) consists of a disk drive attached directly to a server. Data is transferred using Small Computer System () commands, the most common means of I/O communication between a computer and a hard drive. In many implementations requiring large amounts of storage, the storage is a shelf of disks, or a disk subsystem. Internal/External Storage Optional Controller Figure 1. Two Typical DAS Configurations s All applications are insulated from dealing directly with the disk drives. The s operating system incurs the overhead of the entire flow and management disk I/O. It provides the physical disk translation through its local file system and logical volume management through a volume manager. DAS works well in environments with a limited number of servers. However, if there are dozens of servers and significant data growth, the situation rapidly becomes unmanageable. The storage for each server has to be managed separately and can t be easily shared. Scalability is limited, and the overall efficiency of the DAS resource tends to be diminished. With the varied data management needs of today's business functions, enterprises have recognized the need to take a more cost-effective, flexible, and scalable networked storage approach for their valuable high-volume information. Storage Area Networks In a storage area network (SAN), a number of servers have access to a pool of storage resources. Each server utilizes a portion of the storage yet does not know about the other server s data, so the servers share the storage and not the data. The servers are connected via host bus adapters (HBAs) to Fibre Channel switches, which in turn are connected to the Fibre Channel storage system(s). The servers and storage communicate via the Fibre Channel protocol suite, which allows commands to be transmitted via serial connections. The Fibre Channel interface and
protocol allow for high throughput, and are typically only used in the most elite and demanding performance applications. Component costs are high and complexity of maintenance can make SAN implementations an undesirable choice. FC HBA Fibre Channel Protocol Costly, High-speed Infrastructure Fibre Channel Network Block-level Data Fibre Channel Protocol JBOD Subsystem Subsystem Figure 2. A Typical SAN Configuration OR or FC Total Cost of Ownership The total cost of ownership (TCO) for operating a Fibre Channel SAN, while lower than the DAS model, is still relatively high. Although SANs benefit from the efficiencies of centralized management (which reduces TCO), the deployment cost for Fibre Channel is high. In particular, a shortage of specialized operations staff has historically been a problem. Complexity and SAN Islands Another issue with SANs stems from Fibre Channel being a serial interconnect, not a true network. Fibre Channel has no built-in routing capabilities and has only rudimentary address management capabilities. Also, SANs are continually plagued by interoperability issues with multi-vendor deployments. While some interoperability issues have diminished, most SANs today are still single-vendor storage environments. world, and incorporates volume manager and file system capabilities into the storage device. In a NAS environment, the servers are connected to the storage by a standard network. They use network file sharing protocols, like Network File System (NFS) for UNIX/Linux and Common Internet File System (CIFS) for Windows to store and transport files over the network. NAS devices share a common data store, separate application services from file services, and share files among all clients. Many companies have found NAS devices deliver the lowest TCO of any storage approach, and because they have lower capacities and lower performance, when compared with SAN storage, they have found their place in numerous locations around the edge of an enterprise network. More recently, however, the proliferation of Gigabit and enterprise-capable NAS servers has greatly accelerated the deployment of NAS solutions, bringing them closer to the mainstream enterprise applications in data center environments, particularly when ease of use is important. NAS can be very useful for companies needing to share files. They are usually managed individually, though some companies like Snap Appliance do have unified management tools, and each NAS device on the network is accessed by a single IP address. The Need for IP Storage Networked storage is a mature and well-understood technology. Many analysts believe that the main issues slowing the transition from DAS solutions to networked storage solutions are the cost and complexity associated with Fibre Channel. However, a rapidly emerging new technology promises to address both issues: Internet (i) or over IP. page 2 Network Attached Storage Network Attached Storage (NAS) is a true, mature, networked storage solution based on IP and that has longstanding maturity and robustness from decades of use in the networking CIFS/NFS File-level Data NAS Figure 3. A Typical Network Attached Storage Configuration i over Gigabit i is a new Internet Engineering Task Force (IETF) standard protocol for encapsulating commands into TCP/IP packets and enabling block data transport over IP networks. i can be used to build SANs (termed: IP SANs) using a standard Gigabit infrastructure. A standard Gigabit port on a server or switch can now connect to both block and file storage resources over. High-level management activities such as device access, authentication, device information, and configuration are managed using stan-
page 3 Host Initiator i Initiator Data or Data Request i dard applications or tools. For this reason, the deployment of robust, interoperable i solutions is occurring rapidly. Performance First-generation i performance is well suited for the workgroup or departmental storage requirements of medium- and large-size businesses. The availability of TCP/IP engines that increase access speed by offloading network protocols further improves the performance of i at 1 Gigabit, and will allow vendors to further scale performance to 10 Gigabit i in the near future. CIFS/NFS/i Block & File Level Data IP Packet NAS i Target r Figure 4. NAS Configuration for i over Gigabit s How it Works i communications over an existing connection requires a host-side Initiator and a Target software driver in the NAS. The diagram above is essentially the same as in the previous NAS description in the fact that the host and NAS device are communicating over TCP/IP; but with the addition of the i Initiator software driver to the host configuration; and a Target driver to the NAS device. The interaction between the Initiator and Target mandates a server-client model, illustrated in Figure 5, where the Initiator and the Target communicate with each other using the command and data set encapsulated over TCP/IP. At the moment, there are very few i target devices; Snap Appliance is one of the first i implementations to provide i target support on all its GuardianOS v3-based servers. IP Network IP Packet i Figure 5. i Data Transfer Flow i target Many companies are developing i Initiators. Some of the first releases of i Initiators have come from Microsoft, Cisco, Linux, and UNH (University of New Hampshire). However, most have yet to release i Target drivers. Snap Appliance, the volume leader in NAS solutions, is one of the first that has embedded i target support in its Snap s, providing true concurrent block and file support in single Snap. Benefits of i By combining,, and TCP/IP, Gigabit i delivers these key advantages: Builds on stable and familiar standards since protocol and the component technologies based on are prevalent in the enterprise environment Creates a SAN with a reduced TCO installation and ongoing maintenance costs are low Provides a high degree of interoperability reduces disparate networks and cabling, and uses regular switches instead of special Fibre Channel switches Delivers a solution with no practical distance limitations since IP datagrams can travel over the global IP network File and Block Separation in the Enterprise Since some enterprise applications are architected to view storage as a local, direct-attached disk (block data,) NAS has not been suitable for those applications. In a typical corporate IT environment, databases require access via block access. Conversely, users require access via CIFS or NFS file services. Today, this means that a different storage device must be deployed for each access topology. Applications that best utilize SAN storage to support block-based data and the applications that best utilize NAS storage for file-based data are forcing enterprises to use disparate dedicated storage devices. Until now. Snap Appliance Block and File Unification The industry is starting to respond to this challenge with storage systems that have unified both block and file capabilities and benefit from both protocols. Snap Appliance Snap s running the GuardianOS v3 are our first generation of products supporting both block and file access in a single server with simple, easy-to-use provisioning. One of the true benefits of IP-based storage is that, for the first time, CIFS/NFS/i can travel down
the existing network infrastructure using the Gigabit network and leveraging common switches and wiring. But converging at the wire doesn t solve the provisioning problem. One of the true difficulties with storage has always been its provisioning to meet both current needs and future growth. Storage used to be really expensive, so over-allocating storage was undesirable. Though the release of Serial Advanced Technology Attachment (SATA) drives has brought the cost of storage down, the major cost component of provisioning is an intangible one, as servers deployed for different applications and protocols must also be re-provisioned individually. Traditionally, storage re-provisioning has been performed by using capacity expansion tools. However, today s disk drives are large, resulting in long rebuild times. Unloading/loading of the data on a set, in order to expand it, is too time consuming and tedious for many environments. So, the same problems apply. Converging protocols on the wire and still utilizing individual systems for handling different protocols means that enterprises are doubling up the storage devices on the network, which makes storage resource management more of an issue. Simple, On-the-fly Provisioning Snap Appliance eases the provisioning problem by creating virtual i disk devices, supported by our standard volume management. Essentially, i disks reside on a volume in the Snap, just like files. Both block and data files are converged in the Snap. The GuardianOS with Instant Capacity Expansion (I.C.E.) capability provides an easy user interface for managing real-time expansion of any volume on the Snap. An administrator can easily build a new set and group it with an existing set to form single group. This added capacity then becomes instantly available for expansion for any volume in the group. With Snap s there is a single device on the network for both block and file data rather than two one device dedicated to block and one to file. Host or Client Adaptor CIFS/NFS/i Both File & Block Level Data Snap with Unified Block and File Support Files Services Block R A I D Re-provisioning is done quickly and without compromising I/O performance. The UI makes it simple to create new file shares, add another i disk, resize i disks, and perform other provisioning tasks with point-and-click ease. Resizing is done instantly and without the need to unload/load anything. Snap s can be re-tasked at anytime. IT managers can purchase a Snap to meet their file-storage requirements today; and can completely change their mind and deploy it for block storage. Only the Snap can be re-tasked in an instant, without losing any data. Benefits of Unified Block and File Storage Simplified management (i.e. same for NAS and IP SAN) i disks (FileDisks) can be backed up like any other disk attached to the server Provisioning problems are alleviated since FileDisks can be grown online FileDisks are all protected against mechanical failures Who Can Use It? i or IP SANs with unified block and file will initially be most attractive to organizations with the following environments: Distributed data environments Significant data growth over the past five years Proliferation of Intel architecture servers in divisional, departmental, and workgroup environments Business requirements to consolidate data storage among small servers and their management, and to improve operational efficiency, data availability, and storage resource management Budget and staffing limitations which preclude a Fibre Channel SAN deployment Heavy use of critical business applications that require block storage, and until now, had to be stored on a separate server, including: - Microsoft Exchange messaging solutions - SharePoint portals - GreatPlains financial - Customer relationship management (CRM) - Small to medium databases - Shadow copy vaulting - Practically any nearline storage application page 4 Figure 6. The Snap Advantage
Clients Corporate LAN App s GbE Switch Snap s Figure 7. An i Deployment Scenario i/file Disks i/file Disks i Deployment Examples proliferation is increasing the complexity and expense of storage management in many distributed enterprise environments, particularly for applications experiencing significant data growth. The configuration in Figure 7 deploys centralized network storage for the many server types and delivers significant savings in TCO for applications where a common storage pool is desired or where there is a need for a common block (i) and file (NFS/CFIS) storage pool. Snap s can be backed up with the embedded BakBone NetVault software or backup agents for VERITAS, CA, and Legato. Optional Network Data Management Protocol support provides backup flexibility. About Snap Appliance Snap Appliance is the worldwide volume leader in Network Attached Storage (NAS) products. Today, Snap Appliance offers the successful Snap family of NAS servers. These solutions combine the most reliable and cost-effective technologies with industry-leading ease of integration. Together with worldwide vendor partners, Snap Appliance delivers dependable, simple to use and expandable data storage systems beyond simple networks. The focus of the future is to bring ground-breaking advanced data storage technology to our customers affordably like i-based IP SANs. Snap Appliance Snap s running the Guardian OS 3.0 and above, are the first generation of products supporting both block and file access, support the convergence of NAS and i. For More Information The Storage Networking Industry Association (SNIA): http://www.snia.org/ The Internet Engineering Task Force (IETF): http://www.ietf.org IDC WorldWide Disk Storage Systems Quarterly Tracker, March 4, 2004 http://www.idc.com Conclusion Organizations with server proliferation and data growth problems in departmental and workgroup data centers will be the first to benefit from the introduction of IP storage and i, as they replace DAS and accelerate the transition to more cost-effective and flexible networked storage solutions. As the technology matures and performance increases, i-based storage solutions will gradually expand to displace DAS in high-end data centers and mission-critical environments, making i-based IP SANs ubiquitous. Snap Appliance will continue to contribute to the convergence of unified block and file storage for the distributed enterprise with cost-effective, easily deployed, and easily re-tasked solutions. Snap Appliance, Inc. 125 S. Market St. San Jose, CA 95113-2292 888-343-SNAP (7627) International: 408-795-3600 2004 Snap Appliance, Inc. All rights reserved. Snap Appliance, the Snap Appliance logo, Snap, the Snap logo, SnapOS, GuardianOS, Snap Care, Snap Disk, and Snap Manager are registered trademarks or trademarks of Snap Appliance. All other product names or company names are the property of their respective owners. Specifications subject to change without notice. page 5 070704_Rev5V2