Chapter11.Connection Redundancy in Storage Networks and Dynamic Multipathing


Chapter 11. Connection Redundancy in Storage Networks and Dynamic Multipathing

Upon completing this chapter, you will be able to

  • Participate in planning or analysis meetings discussing redundancy methods used in your organization

  • Analyze dynamic multipathing solutions and products that you are using or considering

  • Participate in planning sessions for provisioning LUNs within storage subsystems

  • Diagram multipathing designs, including all hosts, initiators, and subsystem ports

The construction of a storage network infrastructure needs to balance the competing goals of flexibility and stability. A storage network infrastructure should be flexible enough to allow a large number of systems to use it, but it also needs to provide stable data services that can be depended on to work on-demand. In a world driven by the demands of wireless Internet access, IT organizations must develop methods to make data access as stable and reliable as possible.

Redundancy techniques that remove single points of failure are used to make data access reliable. Storage redundancy techniques such as mirroring, redundant array of inexpensive disk (RAID), and remote copy, which are used to provide redundancy for data, were discussed in the previous three chapters. This chapter looks at the architectures and techniques used to create redundant communications between systems and storage. Redundant communications allow systems to continue operating normally if a failure of some type occurs that blocks communications. Most system designs assume that primary disk storage is available and can fail or shut down if communication with primary storage is lost. Therefore, it is important to provide redundant access paths to storage for high-availability systems.

The first part of the chapter examines the physical machinery of the I/O path and briefly discusses how redundancy can be provided by duplicate components. The second part of the chapter is devoted to the highly specialized techniques of dynamic multipathing, which provide the logic for taking action when I/O communications fail.



Storage Networking Fundamentals(c) An Introduction to Storage Devices, Subsystems, Applications, Management, a[... ]stems
Storage Networking Fundamentals: An Introduction to Storage Devices, Subsystems, Applications, Management, and File Systems (Vol 1)
ISBN: 1587051621
EAN: 2147483647
Year: 2006
Pages: 184
Authors: Marc Farley

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