Storage networks


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Introduction to Storage Networks Standards, New Technologies

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Storage networks

  1. 1. Storage Networks The use Network Concepts to expand the Data Storage. By Ahmed Nour 1 For (S)
  2. 2. Why Storage Is Important • The growing demands for more data by time. • The Data storage requirements for legal regulations. • The increase demand of paperless workplaces. • The growth of file and Database sizes over the years . 2 For (S)
  3. 3. Direct Attached Storage The basic model for storage was the Direct attached storage in which each server have its own Data connected to it. The I/O technique used in this connection was the Small Computer System Interface (SCSI) 3 For (S)
  4. 4. Small Computer Serial Interface It’s the standard way to connect the Disks to the Servers , it's responsible for performing the read , write Commands of the Operating system on the Disk, also it uses a Bus (16 Bin). It has some limitations • The maximum SCSI cable length is 25 Meter • The Maximum Number of Attached Devices is 16 Device • It's difficult to connect more than one servers to a same Disk which is required to maintain the High availability. 4 For (S)
  5. 5. Storage networks Network by definition is connecting two or more computers to allow resource sharing and enhance communication. And the resource that we need to share is the Storage. 5 For (S)
  6. 6. Network Attached Storage Using the Traditional LAN, Assign a HUGE Storage to a server and Share this storage to the other servers and desktop by a well-known file sharing protocol (NFS and CIFS). 6 For (S)
  7. 7. NFS and CIFS • Network File system (NFS ) – is an application layer protocol was initially created By SUN Microsystem (NFS sv2 RFC 1094) on march 1989. In depends originally in RPC. in which the a machine can run some procedures in a remote machines . Used to share a folder to UNIX and Linux machines . the current version is NFS sv3 • Common Internet File System (CIFS) – intended to provide an open cross-platform mechanism for client systems to request file and print services from server systems over a network. It is based on the standard Server Message Block (SMB) protocol widely in use by personal computers and workstations running a wide variety of operating systems but widly used with MS Windows Operating systems . 7 For (S)
  8. 8. How NFS and CIFS work 8 For (S)
  9. 9. NAS Limitation and Problems • It's a File level technique not a Block level one . • By design the required file from the san must be processed in the NAS Server or in the NAS Gateway in order to transfer it to the client • The Known Protocols for File shearing (NFS/CIFS) use the TCP/IP stack which by default make a process overhead in the NAS Servers and Client. • At the end of the day the The NAS server or NAS Gateway it's a server with a limited network and processing capacity. 9 For (S)
  10. 10. Storage Area Networks • As discussed before we use a network Concept to Solve the problem of Storage Limitation In the DAS we use the LAN in order to share a Specific File or Directory to a server and this is suitable for file sharing applications but not for Intensive I/O applications such as Databases • The next step is to find another Network that carry the SCSI commands Directly from the OS to the Storage system , this network must be FAST and reliable one 10 For (S)
  11. 11. Fibre Channel SAN • Fiber Channel is a multi-layered network, based on a series of American National Standards Institute (ANSI) standards which define characteristics and functions For moving data across the network. These include definitions of physical Interfaces, such as cabling, distances and signaling; data encoding and link Controls; data delivery in terms of frames, flow control and classes of service ,Common services, and protocol interfaces. Why Fiber Channel • Serial transmission for high speed and long distances • Low rate of transmission errors • Low delay (latency) of the transmitted data • Implementation of the Fiber Channel Protocol (FCP) in hardware on HBA cards to free up the server CPUs 11 For (S)
  12. 12. Fibre Channel Connectivity • Point to point connection, Bi-direction Connection between 2 devices only • Arbitrated Loop connection, a unidirectional connection form a Ring , in which only 2 devices can communicate at a time • Fabric connection, a unidirectional connection that lets all the devices to communicate in the same time using a Switch (Fabric Switch) 12 For (S)
  13. 13. Fibre Channel Node Types Port Type Function N-Port "N for node" port for servers or storage device can work for Point – to – point or fabric topology F-Port "F for fabric" a fabric switch port can communicate with N-ports L-Port "L for Loop" an arbitrated loop port NL-port Modern Ports can work both as a N-port or L-port FL-Port Modern Ports can work as F-port or L-port E-port "E for Extended" Ports used in the fiber switches to link 2 switches G-port "G for generic " modern switches use G-ports to configure itself automatically B-port "B for Bridge " used to link the switch to a different protocol or network 13 For (S)
  14. 14. Fibre Channel Protocol Stack 14 For (S)
  15. 15. Fibre Channel Frame • FC frame is 2148 bytes maximum • 24 byte Header • Source / Destination address • Type indicates the type of frame (Data or Control) • Sequence count , ID • Exchange ID 15 For (S)
  16. 16. Fibre Channel Disadvantages • Complexity • Very expensive • Needs a totally separated infrastructure to build a storage system in the data center. 16 For (S)
  17. 17. iSCSI SAN iSCSI is a block-level protocol that encapsulates SCSI commands into TCP/IP packets, and thereby leverages the investment in existing IP networks. The iSCSI architecture is similar to client/server architecture. In this case, the client is an initiator that issues an I/O request and the server is a target (such as a device in a storage system). This architecture can be used over IP networks to provide distance extension. This can be implemented between routers, host-to-switch . 17 For (S)
  18. 18. iScsi Protocol 18 For (S)
  19. 19. iSCSI Disadvantages The main problems in the ISCSI SAN is the performance . The ISCSI By default use the TCP/IP stack which make an overhead on the CPU of the system, and increase the latency comparing with the Fibre Channel SAN. 19 For (S)
  20. 20. Fibre Channel o Ethernet Fibre channel over Ethernet, or FCoE is a new storage networking protocol that supports Fibre Channel natively over Ethernet. FCoE encapsulates Fibre Channel Frames into Ethernet frames , allowing them to run with traditional Internet Protocol . The main requirement for FCoE • Converged Network Adaptor (CNA) which act as Traditional NIC and HBA at the same time • FCoE Switch which is a network device that will connect to existing LAN and SAN environments. • The Link that FCoE traffic uses must provide the same level of lossless behavior that can be found with fibre channel environment and this could be done using the 10G Ethernet devices . 20 For (S)
  21. 21. FCoE Protocol Stack 21 For (S)
  22. 22. Conclusion As Discussed Using the Network Concepts in order to get over the traditional Storage limitation is a very successful , it gives the ablilty to consolidate the storages into a centralized devices which are easy to manage , make the backup very easy to handle makes its possible to create an effective Disaster recovery sites , the new technology of the FCoE SAN expected to unify the network traffic of the data centers . 22 For (S)
  23. 23. Refrences • U. Troppens, R. Erkens, W Muller-Friedt, R. Wolafka, N. Haustein,,“Storage Area Networks Explained, Basics and Application of Fibre Channel SAN, NAS, iSCSI, Infiniband and FCoE”, Second Edition, pp.59-100, 2009. John Wiley and Sons Ltd., ISBN: 978-0-470-74143-6. • Wikipedia For Fibre Channel Protocol • Fibre Channel over Ethernet: A Beginners Perspective, Harshada Kshirsagar, Pooja Ramrakhyani, Tejashri Vinode, 2011 • Fibre Channel over Ethernet Detailed Review White paper 2011 • IBM Redbook Introduction to Storage Area Network 2006 • Fibre Channel Fundamentals by Tom Weimer white paper • Storage network industry assoistaion 23 For (S)