Introduction To San
- 1. Introduction to SAN -- Jayaprakash Aridoss
- 2. Agenda Storage Area Networking - Introduction Components of SAN Interface Technologies SAN topologies The Signs of a SAN Benefits of SAN Open Discussion
- 3. Storage Area Networking - Introduction What is SAN? SNIA defines a SAN as "A network whose primary purpose is the transfer of data between computer systems and storage elements, and among storage elements. A SAN consists of a communication infrastructure which provides physical connections, and a management layer which organizes clients are the storage The the connections, elements, and computer systems so that data transfer is point of a SAN. access secure and robust." The major components in this layer are the A typical SAN architecture servers, the HBAs, including the GBICs, and the software drivers that enable HBAs to communicate with the fabric layer. This is the middle layer of a SAN, the network part of a SAN, where hubs and switches tie all the cables together into a logical and physical network. This is where all the data resides on the disk drives
- 4. Components of SAN Fibre Channel SAN environments and components enable the development of solutions that provide high performance and high availability, which are the fundamental requirements of a storage network. Fibre Channel devices effectively combat the problems related to bandwidth, which generally occur during bulky operations, such as backup and restore operations. Hardware components offer different features to provide for a small SAN to a high-speed and high- volume SAN data center. A wide range of hardware and software products make up the components of a SAN. SAN components include: Hubs •Serve as the access point for the clients •The hubs on a storage network are used to implement the ring-like Fibre Channel Arbitrated Loop •Provide load balancing and data caching to improve performance Bridges Unlike the hubs Client layer•Schedule backups (FC-AL) Bridges provide the abilityused in traditional networks, a typicala Fibre devices inhub can They topology. Channel support up to 126 nodes. Hubs haveto connect parallel can bedevices to Fibre Channel network. 7 to 12 ports that SCSI used to connect a Fibre HBA: Channel perform a protocol conversion function between SCSI and Fibre Channel. configuration. •HBAs are similar to NICs used in are alsoand other non-SAN networks. They replace Note: Bridges LANs referred to as Fibre Channel SCSI routers. Host layer the traditional SCSI cards and interconnect SAN devices, such as servers and Switches Servers storage devices. Multiplexers •Switches provide many more connections than hubs and are used in FC-AL and switched fabric HBAs configurations. They offer 8 to 16 ports, and of single switch interleave signals from multiplesmall- Multiplexers are a special category a bridges that alone enables the creation of a devices and Routers transmit them simultaneously through a single transmission medium. scale SAN. Switches offer a dedicated bandwidth of 100Mb/s and above for each port, enabling SAN software Channel routers provide an speeds. among IP-based devices, LANs, and the Fibre is required interface frames to be routed between SANto manage and troubleshoot a SAN environment. SAN nodes at high softwarestorage effectively uses the available network bandwidth. is used network. These devices transfer storage data between different networks by A multiplexer to manage: Fabric layer using various transmission media and addressing methods. Hubs or switches Hardware and is a multilayered SAN (such as storage, switches, and hubs) Fibre Channelsoftware within the network based on a series of standards from the Bridges and multiplexers Multiple Gateways Standards Institute (ANSI). These standards define characteristics storage enclosures American National Multiple Fibre Channel gateways enable interconnect networks using different protocols and and functions forsystems data across the network. They include definitions of operating moving Routers and Gateways Multiple addressing such as cabling, distances, and signaling; data encoding and link not be interfaces methods over a wide area network (WAN). However, they might physical vendors SAN software Resources toto performon in different frames, flow locationsand classes of service; Storage data delivery protocol conversion. able controls; can be managed SCSI or of geographical control, based in terms Fibre Channel. Fibre Channel Ex., Brocade Fabric OS,protocol interfaces common services; and Tivoli Storage Manager, HP-OV SAN manager Fibre Channel-based storage enables direct connection to the Fibre Channel network, Backup and recovery system enhancements over SCSI. from an external tape drive providing distance and speed configurations can range Storage layers attached to the corporate server, to large tape libraries capable of handling hundreds of SAN uses the following storage devices: A backup media. Storage devices JBOD, Tape libraries, Stroage drives, Storage Arrays Ex., Tape libraries, Auto loaders Backup devices
- 5. Interface Technologies Fibre Channel can be considered the Ethernet of SANs and is the standard that all major vendors support. FCP - mapping of SCSI over FC It has been around for more than 10 years and is used in major corporations worldwide. If you want a mature technology with wide support, Fibre Channel is an excellent option. iSCSI - mapping of SCSI over TCP/IP (Emerging Technology & Comparatively slow ) InfiniBand A new contender in the SAN arena is Internet small computer system interface (iSCSI), an IP-based standard for linking storage devices over a network. The iSCSI protocol runs on top of a high-speed LAN infrastructure as another Transmission Control Protocol/Internet Protocol (TCP/IP) application, so you can use your existing network for a SAN without having One of the newest SAN networking technologies is InfiniBand, which offers support from to build a new infrastructure. major manufacturers but is still fairly new. Unlike the Peripheral Component Interconnect (PCI) bus used with other networking technologies, InfiniBand can carry multiple channels of data at the same time to improve throughput. With a low-overhead protocol and high-speed throughput, InfiniBand could overtake Fibre Channel in the future.
- 6. SAN Topologies A topology is a physical layout diagram showing how network devices are connected with each other. The Basic SAN topologies are: Point-to-point — A dedicated and direct connection exists between two SAN devices. Arbitrated loop — The SAN devices are connected in the form of a ring. Switched fabric — SAN devices are connected using a direct connection between fabric switch In the point-to-point topology, there is a fabric switch. The the devices. enables a SAN device to connect andofcommunicate dedicated entirely to that transaction. As a The bandwidth that connection is with multiple SAN devices The result, transactions are serialand relatively error free. logical point-to-point FC-AL topology is a fast interface that creates However, a SAN based simultaneously. connections between topology is expensiveSeveral Fibre Channel arrays and exclusively on this ports on the loop. for large enterprises. Switched fabric multiple servers could be on the FC-AL. A simplified FC-AL consists of a: A Fibre Channel switch transmits each packet only to the port connected to the destination device. Server equipped with a Fibre Channel HBA. Components Fibre Channel storage hub. A simplified FC-SW contains a: Fibre Channel storage array with a Fibre Channel array controller installed. Server equipped with a Fibre Channel HBA. Fibre Channel storage switch. Fibre Channel storage array.
- 7. The Signs of a SAN In summary, a SAN is a combination of hardware devices, interconnect strategy, and concept. Even as the capabilities of the hardware and speed of the interconnect change, the concept will remain stable. A collection of servers, mass storage, interconnect devices, and interconnection media constitutes a Storage Area Network, if it exhibits most of the following characteristics: Storage is behind the server Storage devices are connected to each other Multiple servers are connected to the storage pool Heterogeneous servers may be connected to the storage pool Fibre Channel connectivity (fiber optic cable and FC host bus adapters)is used Fibre Channel hubs and switches are present Multiple paths to devices exist
- 8. Benefits of SAN SAN benefits provide high return on investment (ROI) and reduce the total cost of ownership (TCO) by increasing performance, manageability, and scalability. However, SANs are not for everyone. Sometimes the benefits do not justify the costs for small companies. A good guideline is the use of 16 servers. If you have more than 16 servers, a SAN should be beneficial. Some key benefits of SANs are: Reduced data center rack and floor space — Because you do not need to buy big servers with room for many disks, you can buy fewer, smaller servers, which takes less room in the data center. Disaster recovery capabilities — SAN devices can mirror the data on the disk to another location. Increased I/O performance — SANs operate faster than internal drives or devices attached to a LAN. Fibre Channel SANs offers these additional benefits Performance — Distance and speed Efficiency — Reliability and nondisruptive scalability Manageability — More devices supported with less people Connectivity — Any-to-any connections Cost effectiveness — Serverless backups and tape library sharing Modular scalability — Dynamic capacity Consolidated storage — Sharing of centralized storage
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