Storage Networking

The sections below cover the fundamentals of storage networking and offer explanations of how it should be deployed. To go directly to a section, click on one of the links:

What is Storage Networking?
The Business Benefits of the Storage Networking
Deploying Storage Networking in the Corporate Environment
Issues with Storage Networking
The Future of Storage Networking
Further Resources for Storage Networking

What is Storage Networking

Networked Storage, or the networking of storage, involves creating an environment in which storage hardware (in its simplest form, hard disks, tape drives and so on) can be directly attached to a network. There are two ways in which this can be done:

Create a network (of protocols, devices etc.) exclusively designed for, and hence optimised for, storage. Storage devices of all forms can be arranged in a form that best suits storage needs, for example data can be mirrored to a fail-over site. Also many data transfers (say, backups) can take place without taking bandwidth away from the regular network, or processor time cycles from servers. This model gives us Storage Area Networking, or the SAN.
Create devices which uses regular network protocols (usually Ethernet) but which are built from the ground up to store and retrieve data. Such special-purpose “appliances” can be optimised for performance criteria such as data throughput, reliability and information integrity. At the same time, they can be built more cost-effectively than general-purpose devices (regular computers to you and me). This model gives Network-Attached Storage, or NAS.

Let’s face it, most people couldn’t give an orang-utan’s elbow for the differences between SAN and NAS. In the future, it is fully expected that the two models will merge. Meanwhile, we are faced with both. To gain an in-depth view of SAN principles, you need look no further than the classic paper by Michael Petersen of Strategic Research. Dell has produced a good paper on NAS and how it fits with SAN.

For a one-page comparison of the differences between NAS and SAN, click here.

Business Benefits of Storage Networking

The business benefits of storage networking in general may be summarised in one word – value. Correctly specified and implemented, a pure storage environment is able to deliver a better, faster storage service at a lower cost. To dig deeper into the financial implications of this “value” thing, refer to the Gartner paper on the TCO of Storage here.

As for the benefits of each storage type:

For NAS, you could check out the Network Appliance article here – however note that the architecture section is specific to NetApp’s own products.
For SAN, Hewlett Packard puts things short-and-sweetly here. See also Compaq’s offering here, if only for the snazzy graphics.

There is a succinct (and perhaps more objective) summary of the benefits of each, here.

Deploying Storage Networking in the Corporate Environment

Storage is just hardware, right? Wrong. Deploying storage is primarily about understanding (and therefore meeting) the information management needs of your organisation.

CommVault have collated a good set of questions to ask the vendor of a given security solution. You should be unsurprised that CommVault’s own offering satisfies all the criteria they set… CNet has a useful buying decision checklist, here.

To use networked storage to manage a database environment such as Oracle, see the Veritas article here.

Issues with Storage Networking

The following issues are open:

The most fundamental storage management application is (still) backup and restore, described here.
Interoperability has long been the bane of the SAN. It was being discussed two years ago, and according to the ZDNet article of December 2000 “storage suppliers are finally heeding their customers' calls for interoperability.” In other words, it ain’t over yet.
Scalability of storage is a problem solved, but it has to be implemented. An article on how to address storage scalability can e found here
Storage Management is still a black art, with organisations such as the Storage Networking Industry Association (SNIA) and the Distributed Management Task Force (DMTF) still grappling for standards. At least the SNIA has a paper on what needs to be managed in a SAN.

The Future of Storage Networking

May we once again lean on CNet? They have a one-pager on the future of storage here, covering standardisation, infrastructure advances and the arrival of the Internet.

Like other applications and service, storage is going “virtual” as described in the PC World article here. Network Storage Forum article here proposes storage management as a service, but concedes that such solutions are still very much in development. To further the cause, as described here the iSCSI standard is being pioneered, which will enable the final convergence between storage networking standards and, thankfully, the demise of the terms NAS and SAN.

Further Resources on Storage Networking

Network Computing storage pages - a comprehensive, structured starting point for all things storage.

SearchStorage - and another one! Take your pick.

The Storage Networking Industry Association – a useful, resource

The Distributed Management Task Force – a highly uninformative site, included for completeness – the DMTF has an overlapping remit with the SNIA.