Storage

Foundations of Network Storage, Lesson One: SAN

In lesson 1 of 5, we'll delve into considerations surrounding the storage area network (SAN).

Foundations of Network Storage: Lesson 1 of 5.

In this lesson, we'll explore the storage area network (SAN). Topics include how to decide if a SAN is best for your organization, your choices regarding SANs, and the tools you need to support a SAN.

A Storage Area Network is the most expensive storage option available, as well as the most complex. However, SANs provide capabilities not found in other solutions and, in the right situation, can help you improve the bottom line, even considering the expensive initial outlay.

SAN advantages

SANs today come in two flavors: Fibre Channel, and iSCSI or IP-based SANs. Fibre Channel is the most well known type of SAN, but over the last couple of years, iSCSI-based SANs have started to hit the market in a big way, mainly due to their good performance and much lower cost versus Fibre Channel.

SANs truly combine the best of both NAS and DAS storage. For example, with a proper implementation, you get a completely redundant storage network that is eminently expandable to, literally, hundreds of terabytes a la NAS, but you also get block-level access to the data just as you get with DAS. You can also access data at a reasonable speed, making SANs good even for operations that require significant disk access. With a SAN, you also get centrally managed storage with the ability to provision space on-the-fly. Even better, with some implementations, you can configure your servers with no internal storage and require that all systems boot directly from the SAN (Fibre Channel only). Talk about plug and play!

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SAN drawbacks

With all of these great points, what are the downsides of a SAN? There are two major drawbacks to a SAN: cost and complexity, particularly when it comes to Fibre Channel implementations. A reasonable Fibre Channel SAN can start in the $50-60K range for just a terabyte or two of storage. On the other hand, newer SANs based on iSCSI might start in the $20-30K range, but aren't quite up to the performance levels of their Fibre Channel cousins. The difference in price is mostly due to iSCSI's ability to make use of off-the-shelf gigabit Ethernet hardware, whereas fibre channel requires specialized, expensive equipment.

For a collection of resources on Storage Area Network, see page two.

SAN Resources

  • Make the best SAN choice with this storage comparison chart
    This downloadable chart provides a quick-glance comparison of some of the storage products and servers available from Dell, HP, and IBM, and lists specifications and features for direct-attached SCSI storage, NAS, iSCSI, and fiber-channel-based SAN solutions.
  • From Microsoft.com: Microsoft Windows Clustering: Storage Area Networks
    This document describes what storage area networks (SAN) are, how server clusters can be deployed in a SAN, and how the Windows platform, and Windows clustering in particular, take advantage of SAN technology.
  • Storage Basics: Storage Area Networks
    This article introduces the SAN and examines its role in modern network environments and whether it meets the storage needs of today's organizations.
  • Planning storage solutions that grow with your business
    Choosing the right storage solution for your growing business isn't a "no brainer." You have more choices than ever, and scalability and performance must be weighed against ease of use and the ever-present budget considerations. Here's how planning now can save you money in the long run.
  • Case study: Using a SAN to increase uptime and decrease backup times
    An IT manager at a healthcare company decides not to go with a low-cost solution such as network attached storage devices. Instead, he opts for an expensive SAN. Find out why knowing the business implications of this decision lets the investment pay off.
  • Webcast: SAN Lessons Learned
    When Brocade Director of IT, Jim Ravelli, implemented a SAN last year, he went through many of the same steps you might encounter in migrating to a SAN architecture. In this free webcast "SAN Lessons Learned," Jim will describe the Brocade IT environment before the SAN, and the steps involved in implementing and managing the SAN to support mission-critical information and applications.
  • Discussion: SAN backup drive being fragmented. Should I defrag?
    A TechRepublic member has 16 drives in the SAN with about 1tb of space, split into two logical drives for access for two separate servers. One of the partitions is badly fragmented. Should he be running defrag on these drives? Read what another member advised.
  • Discussion: Multi-server reads to same set of SAN disks
    Is it possible to store a single copy of the same read-only content within an EMC SAN (DMX2000 and DMX3000) and allow multiple servers to read the content?
  • Blades break down barriers
    In the traditional data center, storage, network and server experts don't tread on each other's turf. But as these tiers converge in blades servers, there's potential for a big shake-up. Tim Golden, director of PowerEdge server marketing for Dell, explains in this Whiteboard Video.

White Papers

  • Improving SAN Performance and Reliability With the NetWisdom SAN Performance Monitoring Tool
    NetWisdom can be used to develop a SAN performance baseline and verify that the SAN is performing as expected according to the baseline. Using the performance baseline, SAN administrators can establish a service level agreement with customers and measure the SAN performance against this SLA.
  • Choosing the Best Architecture for Data Protection in Your SAN
    Download this HP white paper to learn more about the factors that contribute to the notorious lack of reliability in SAN-based backup solutions and why a growing number of enterprises are solving that problem by deploying intelligent, controller-based tape library architectures.
  • SANFS Maestro: A SAN File System Planner
    Manual planning of storage infrastructures that are large and that utilize heterogeneous devices has become a time consuming and error prone process. This problem becomes even more complex when one is designing storage area network file system (SAN FS) based storage solutions. SAN FS systems that combine the benefits of both SAN and network attached (NAS) systems have been proposed as a mechanism for designing scalable storage infrastructures. This paper proposes a SAN FS capacity planning tool that takes application level requirements, best practices, and other types of policy input to design the necessary SAN FS logical and physical constructs.

SAN Vendors

Course list

  • Lesson 1: SAN
  • Lesson 2: NAS
  • Lesson 3: Fibre channel/iSCSI
  • Lesson 4: Backup
  • Lesson 5: What's next?

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