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SANE or INSANE?

From STORAGE Magazine Vol 6, Issue 9 - December 2006

The notion that SANs - Storage Area Networks - are difficult to administer still prevails. Is it madness therefore to take this direction - or are there management strategies that, once implemented, make it the way forward? most of all, what gains are waiting to be enjoyed by heading down the SAN route anyway? editor Brian Wall investigates

There's no denying that most users welcomed the promise of Storage Area Networks - or SANs - as a more efficient way to manage storage growth, improve storage utilisation and add higher levels of data protection. However, there was also a feeling in the early years that adopting a SAN strategy came at a price - both literally and also in terms of its perceived complexity.

On top of that, a lack of management software at that time made SANs appear to be the kind of solution that was practical for high-end enterprises only. Of course, SANs have made major advances since then, yet these early perceptions still prevail and have inhibited many new users from enjoying the benefits that SANs provide.

"As little as four years ago, SANs were defined as Fibre channel-based networks that required specialised switches and highly skilled experts to operate them," comments George Teixeira, CEO, DataCore Software. "Also, SAN components were new then, therefore many incompatibilities existed amongst vendor offerings. However the biggest problem - the insanity - was the lack of management software that made these networks easy to set up and use. Today, new technologies, such as iSCSI, enable SANs to be constructed using standard Ethernet LAN networks.

“Virtualisation software meanwhile has advanced, so that storage can be managed and allocated with a 'point and click'. And new auto-provisioning technologies greatly reduce the time to provision new storage and systems, while optimising the utilisation of storage assets."

It is certainly the case that new users considering a SAN can start small and learn, before carrying out a wide-scale deployment. It is even possible to build a SAN with an existing LAN infrastructure. More importantly, software virtualisation is now available at prices that fit the small to mid-size business markets, enabling users to see how easy it is to manage a storage network and gain confidence in the process.

"With software and virtualisation," adds Teixeira, "SANs become practical to manage, and therefore the real benefits and the promise of SANs can now be realised." In fact, he highlights several benefits he maintains can be derived from implementing today's SANs, including:

• Higher rates of storage utilisation - from 25-45%, to as much as 90%
• Greatly reduced downtime. Typically, a non-SAN achieves 98% uptime (60 hours a year). Virtual SANs typically reduce downtime to under an hour
• Higher productivity. Features such as auto-provisioning eliminate time-consuming tasks and can increase productivity by a factor of 4-10X

Data, data, data!
So what are the driving factors that have made SANs a so much more believable contender? First of all, in an effort to continue to improve business productivity and customer service, most organisations are deploying data-intensive applications.

"This has resulted in a sustained increase of information stored and has greatly elevated the importance of a sound storage strategy," says Ian Bond, data centre consultant, Cisco Systems UK & Ireland. "Selecting a unified architecture that integrates the appropriate technologies to meet user requirements across a range of applications is central to ensuring storage support for mission-critical systems. Matching technologies to user demands allows for an optimised storage architecture, providing the best use of capital and IT resources."

Bond believes that SANs have emerged as the best solution for these advanced storage requirements. "Often SANs can alleviate many, if not all, of the pain points of IT managers, since they allow for more manageable, scalable and efficient deployment of mission-critical data, enabling ease of management, increased sub-system utilisation and a reduction in backup expense. When compared to a Direct Attached Storage (DAS) environment, not only do SANs provide advanced functionality, but they also contribute to lowering an organisation's total cost of ownership and providing significant positive return on investment."

According to Bond, centralised, efficient management, intelligent SAN services, a robust and flexible platform and global, 365 x 24 x 7 service and support are all requisites for any organisation seeking to realise the positive benefits of SAN deployment.

"Any solution that closes off heterogeneous options - whether it is protocol, vendor, or equipment specific - will only be a transient solution, with limited strategic and ROI justification. The optimal SAN solution will have a robust, high-performance architecture that creates new opportunities and alternatives, while protecting resource investments from unexpected turns in the economic environment and changes in market adoption of new technology."

He adds that some management tools for SANs, such as those provided by Cisco, provide a simple-to-use, graphics-based tool set that manages devices and overall SAN fabrics, and can gather data and report on the behaviour of multiple SANs over extended time periods. "Coupled with open, standards-based interfaces that enable integration with other management applications in the data centre," he concludes, "this is simplifying and improving the management of SANs and the wider application delivery systems."

DAS-ed and confused
In a world where inexorable data volume growth is a given, the decision to switch from DAS 'islands' to a single SAN pool is typically taken specifically on the basis of easing the 'management' challenge: better, more cost-effective management of data overall. But is the fear of not being able to manage the SAN effectively itself holding back adoption?

"Well, the tasks involved in managing the SAN are, in the main, the same as those in managing a single DAS island," says Nigel Ghent, UK & Ireland marketing director, EMC. "The principle difference lies in configuring and managing the fabric/switch infrastructure - and management tools have been readily available for a number of years. So the real issue becomes not so much the availability of these tools, but more the lack of expertise in using them. In other words, it's an education issue."

To overcome this perception, he argues, the key SAN management strategies should be to implement appropriate SAN management tools - for zoning, LUN masking and switch configuration and ongoing management, etc - and then to train staff accordingly.

"A true, heterogeneous SAN implementation brings benefits, in terms of the ability to better manage ever increasing data volumes, without adding human resources, which, let's face it, are the most expensive part of any storage environment," Ghent adds.

"Consolidation from multiple DAS islands to a SAN often means less hardware, but almost always means easier management."

In other words, more information in a single place, rather than spread through the infrastructure. "The backup process can be made much easier, with a single, rather than multiple, backup applications and backup devices, and remote replication becomes easier, too, with a single replication tool. Meanwhile, the day-to-day capacity management and provisioning at disc/device level are the same - you simply eradicate the duplication going down the SAN route."

How do you solve a problem like …
An alarming realisation about data growth issues is, of course, that there is no crystal-clear picture of how to solve the problem. Traditionally, businesses have adopted Network Attached Storage (NAS) solutions, which enable them to bolt on other NAS as the volumes of data increases. As businesses are still almost exclusively focused on the bottom-line with regard to IT implementations, they have been reluctant to adopt SANs to manage and control their data. They see this very much as an expensive and high maintenance way to go, putting a heavy strain on resource.

"Current perceived issues around SAN deployment are necessary, especially with regard to fibre channel solutions," says Paul Klinkby-Silver, VP Europe, EqualLogic. "Fibre channel is notoriously complex and, if an IT department of a small or medium-size business does not have this expertise in-house, they pay dearly to their vendor who charges an arm and a leg to perform esoteric management tasks - from configurant RAID sets to expanding LUNS, adding disc capacity and setting up backup processes.

"However, SANs need not be as complex as all this. Networked storage can be achieved through iSCSI. This way, traditional SCSI direct cabling is replaced by device connections to an IP network infrastructure. As well as utilising the skills and technology already in place in the IT department, iSCSI SANs also offer a high level of functionality, including snapshots, replication and backup. Essentially, it is the most efficient way to replicate and store large data volumes quickly, safely and effectively."

Klinkby-Silver argues that an iSCSI SAN delivers comprehensive security more effectively than any other networked storage solution. "With a point-to-point architecture, it is nearly impossible to 'snoop' or 'hijack' packet data, unless you have physical access to the network or administrative access to the switch.”
And he sees such solutions already making huge inroads into the enterprise environment. "A growing number of CIOs and storage administrators are considering this lower-cost iSCSI technology to facilitate a move to a centralised storage environment. iSCSI is beginning to prove its value as a consolidated storage solution that leverages existing skills and infrastructure, all while delivering high performance and platform interoperability."

Hit or myth
In the final analysis, the move to fibre channel SANs - or not - comes down to many factors, not least of which is a continuing and nagging perception of an over-complexity associated with its integration, management and support. This negative view may well have slowed, stalled and even stopped the adoption of SAN storage deployment. Was fibre channel itself inherently too complex to facilitate widespread adoption?

"Time has cleared up many initial concerns," claims Scott Cleland, director of marketing, AMCC Storage, "although FC remains the most expensive communication protocol, unless you have large distances to cover. The technology is further complicated by the backend interface to the underlying disc drives - which can be fibre channel, SAS or SATA - although the fact that SAS and SATA interfaces share basic cabling infrastructure, simplifies the situation.

"Another emerging and contributing issue is the requirement for more storage, with more security and more redundancy, which can oppose the need for IT management simplification and efficiency. Strategies aimed at efficiency and simplification often try to reduce the cost of storage based on content, moving data without overt IT intervention and avoiding duplication, adding to the complexity of storage decisions, particularly when to expand or contract."

So, should it be SAN or NAS, in his opinion? Is it even a matter of choice? "SANs are networks that expose raw blocks of storage," says Cleland.

"Operating systems use pooled virtual storage, a logical device [just like a local hard drive]. The benefit of block storage includes the ability to meet application capacity-performance requirements, without utilising storage unnecessarily, as well as implementing policy-based software management tools that help
to create automated provisioning, in order to increase and allocate storage when needed.

“NAS storage, however, is easy to set up and can be directly attached to existing ethernet network infrastructures, with very little configuration or extra software, but it lacks the performance and flexibility of a SAN.”

The final element in the debate, he feels, comes down to iSCSI and Ethernet. "Software management on the storage system itself is a major challenge, particularly if strategies for dealing with the complexity include delegating file migration to the storage system. For large operations, the biggest return is simplifying the management of the software provisioning aspects traditionally offered by SANs, whereas for small operations the focus is on ease of use in installation and the relative simplicity inherent in NAS. NAS and iSCSI is a blend of technologies that meets the needs of a broad range of end users, offering a serious alternative to traditional fibre channel SANs." ST