Page 1

Real world networking guide

Storage for SMBs

Real world networking guide | Storage for SMBs

Why move away from dedicated storage?

Welcome to the latest in a series of real world networking guides from D-Link, written specifically for small business owners, managers and IT staff looking to get to grips with networking issues.

These guides will tell you everything you need to know in order to understand and deploy key networking technologies. Moreover, because D-Link realises that technical expertise is at a premium in smaller organisations, they will do so with a minimum of fuss, resorting to jargon only where absolutely necessary and explaining what everything means in understandable layman’s terms. This latest guide in the series is focused on deploying dedicated storage solutions in small to medium businesses (SMBs). A number of developments, including a significant reduction in the cost of storage technology in recent times, have made using dedicated, networked storage far more accessible for the SMB community. Moreover, a new wave of technologies has made storage an essential component in many cases. Here we examine how adopting these new technologies adds flexibility, resiliency and lower management and running costs to your infrastructure.

The idea of buying dedicated networked storage for a small to medium sized business may seem like an overkill to many, but it can yield significant business benefits through more efficient deployment of resources and cost savings. The importance of certain business applications changes over time. Ten years ago no one predicted the importance of email or the World Wide Web. Now, every business regardless of size is connected to the web and has its own dedicated mail server. This has led to some unique challenges for companies: We have all experienced the frustration of a mail server going down and the lack of productivity this brings. Similarly, the inability to access files stored on a server results in a loss of productivity, as well as a potential loss of customers, which can be very disruptive to business. However, the majority of computers, including servers shipped today, ship with their own dedicated storage; commonly referred to as Direct Attached Storage, or DAS. DAS is an easy way to attach storage to servers, however it restricts expansion and scalability leading to inefficiencies and difficulty in sharing or repurposing unused storage. How many of us have run out of disk space and had to delete items in order to save something? The advent of networking many years ago created two freedoms. First, it allowed users to be scaled without regard to processors. Second, it allowed users to be geographically displaced from the processors. Storage Area Networks (SANs) do the same for storage, however their current adoption has been restricted to mid to large enterprises, because of the associated cost.

Current IT pain points

Dedicated storage for SMBs – The rationale in a nutshell

• The requirement for 100% uptime

The case for centralised storage is not new for SMBs but it is one that can now be better resolved.

• Growth rate of data • Extended working hours coupled with shrinking back-up windows • Reduced budgets and staffing levels • LAN bandwidth and the need for Disaster Recovery (DR)

The problem for SMBs in the past was that these centralised solutions were simply far too expensive and complex to be rational purchases. Now, however, dedicated networked storage has become an affordable reality even for small businesses. IP-based storage such as NAS filers have become prevalent everywhere, even in the home. However some companies still continue to use risky processes to secure vital company data. In some cases using individual USB memory sticks (with their horrific security issues) to retain and protect their data. Others have unregulated backup procedures, backing data up to a tape drive, without checking to see if the back-up procedure has completed correctly. Windows Server SBS 2007 natively supports the use of external or network drives to protect vital server data, consequently most small companies simply use a network share, and back up across the network. The challenge comes when you need to change the configuration or change the retention period of the data, or even recycle the information from a server. So, rather than simply retaining data on individual servers, or backing up every day to a tape drive, it makes a great deal of sense for an SMB to consider a dedicated, networked storage device and gain reliable, secure data storage that is readily accessible.

Centralising data access also makes data management far easier and more flexible. With this come further cost benefits, especially when it comes to adding and changing server and user access from a day to day administration point. Dedicated storage provides the ability to centralise your storage into a single pool, allowing centralised management of storage and user access. Another benefit of centralised storage is that it is now possible to develop and implement a Disaster Recovery (DR)/Business Continuity (BC) strategy. If your information is dispersed around multiple servers, then it is harder to plan an effective DR strategy, making it more likely for you to lose a vital piece of information should anything happen. Providing managed, secure access to data therefore makes a huge amount of sense. And this is not a case of simply providing password protection for data access, but incorporating a tiered approach to data, applications and service availability. Most back-ups are scheduled for the evenings, so if a disaster does occur, for example at the end of the day, all the transactions performed since the last successful backup will be lost unless Disaster Recovery and Business Continuity provisions are made.

Server Disk



LAN Tape


Real world networking guide | Storage for SMBs

Is your storage fit for purpose?

The cost of data loss – FUD factor or reality?

What are the storage options and available technologies?

So, the ability to easily add capacity to your storage solution is key, and dedicated network storage enables the ability to add additional disk drives easily, rather than having to reinvest in brand new hardware every time you want to increase your storage capacity. This kind of flexibility coupled with the scalability it provides are essential criteria for dedicated network storage, since data storage requirements are increasing almost exponentially.

There is much talk in the media about the cost of data loss to a company, even potentially leading to its absolute demise. But is this simply a case of exaggerated FUD (Fear, Uncertainty and Doubt) factor, or is it a reality for SMBs?

Most SMBs implement one of three storage architectures; DAS - Direct Attached Storage, NAS – Network Attached Storage or SAN Storage Area Networks. DAS is the most popular solution, being implemented by more than 50% of the market.

First, it is important to make the point that a secure, central data repository that is available locally or remotely, 24x7, is clearly a major business benefit and this is what SANs can provide. Moreover, it is possible to incorporate redundancy to provide access to the data even in the event of a problem such as a critical failure caused by flood or fire.

NAS storage has become popular and is usually utilised to provide centralised file sharing across a company network, since it is nothing more than a thin server with storage. SANs have traditionally been restricted to larger organisations requiring centralised data storage and willing to make the capital and manpower investment in Fibre Channel based SANs.

New legislation post Enron, such as Sarbannes-Oxley and Basle-II, mandate what type, how, and for how long data must be retained by every company, therefore putting added pressure on companies to formulate a scalable strategy for the storage of financial and company-sensitive data. These compliance challenges are driving the need for a new wave of applications, such as Video Surveillance, Disaster Recovery and Business Continuity generating very serious amounts of data. It is vital not to underestimate how much storage space is required, not just now, but in 12 and 24 months time. For example the FSA legislates that all voice conversations undertaken by banks and financial institutions must be retained for a minimum of 12 months.

The reality is that many companies now rely heavily – if not entirely – on their network and are regulated to retain data, so any “downtime” where data is unavailable quickly becomes very costly. Worse still, complete data loss can be truly disastrous for a business. And this might happen, not simply as a result of accidental deletion or failed drives, but through security breaches and wilful data destruction.

The main problems with implementing Fibre Channel SANs is their cost, complexity and more importantly interoperability. This does not deflect from the fact that the architectural benefits of a SAN are applicable across businesses of all sizes. Thanks to a combination of the Internet and deployment of high speed LANs (Local Area Networks), implementing SANs without using Fibre Channel is now possible by using the TCP/IP protocol to communicate with the storage array. The emergence of IP SANs (or iSANs using iSCSI – see figure 1) has brought the benefits of the SAN architecture to a broader market, however, until now, there have been limitations with throughput/performance. The introduction and adoption of Gigabit Ethernet is creating a huge inflection point within the market place, since it is now capable of carrying both storage and network traffic.

What is iSCSI? Figure 1 - iSANs using iSCSI Servers NAS Tape





iSCSI – Internet Small Computer System Interface, is an IP-based storage networking standard defined in 2004 for transporting low level disk commands to storage devices, by transmitting classic SCSI commands over IP networks. iSCSI is able to support data transfers over any IP network be they LANs, WANs or the Internet. In this way it can enable location-independent data storage and retrieval. It can now effectively replace Fibre Channel in enterprise SANs. This transition to IP has meant that SANs can now be adopted by companies of all sizes. Incorporating iSCSI technology into the SAN world has simplified deployment, however, and reduced entry costs as well as ongoing training and management costs. Combine this with Gigabit Ethernet and you have a fast, very affordable industry standard solution for dedicated, high-speed storage that is suitable for any size company.

Disk array

It means we can now easily build a SAN using standard network designs, as we can see from figure 2, where the SAN is simply a secondary dedicated storage network, utilising an Ethernet switch.

Figure 2 - DSN-1100 Storage System Diagram Storage Area Network SAN

Local Area Network

Disk array

Two network cards


This simplifies both deployment and management of a SAN, since it is effectively just an extension of the main Ethernet/IP network.

Switch Workstations


Two network cards Workstations

Real world networking guide | Storage for SMBs

What to look for in a dedicated storage solution? So what should you be looking for, feature-wise, in a dedicated storage solution? Here we provide a list of key features and functionality to include in your proposed storage solution. Scalability: A network storage enclosure with multiple bays provides the ability to start small and grow large, on demand, cost effectively providing long term investment protection. Equally you don’t want to purchase a solution only to find that you have to start again a few years down the line. Data Availability: It is important to ensure that your data stays available online 24x7x365, meaning that data redundancy has to be built in. This incorporates various RAID levels, providing both performance and resilience benefits. In the event of a power failure, the storage device should be battery-backed to ensure that data currently residing in the cache memory of the storage array and system RAM is retained to ensure transactions are not lost. Once battery operation kicks in to preserve buffer cache contents, it is recommended to ensure that it has 72 hours of battery life, to allow for a full recovery to take place. Why 72 hours? Well, it ensures protection for the longest period a server will be left unattended – typically a weekend. You’d be surprised at the number of iSCSI solutions that don’t offer this simple feature.

Manageability: Not only is it important to be able to easily manage users and secure access to the data, but bear in mind the manageability of the data itself. Since we are potentially talking terabytes of data here, the ability to easily search and find the storage enclosure, drives and data you need is an essential requirement. Also for companies transitioning from a DAS to SAN environment, a simple web-based management and configuration interface is essential. The storage should be easy to setup and configure in the first place to minimise both deployment time (often critical with getting storage online) and potential human error. The interface should enable users with various access rights to perform different tasks for example, in remote locations users should be able to monitor the storage whilst administrators should be able change configuration all through their log-in rights. Equally, easily scheduled (or real-time) file backup is a must-have feature in order to ensure valuable data is not lost. Typically, backups will be scheduled to run automatically, maybe incremental daily and full-backups weekly. It is vital to be able to easily perform a real-time backup in the event of an emergency situation arising. Most businesses never actually conduct a test restore procedure, meaning that in an emergency under pressure the process is rushed and putting vital data at risk means down time being extended.

Performance: For higher levels of performance and scalability, look for storage systems that can have multiple Gigabit Ethernet interfaces to provide fault tolerant access to your data. Equally it is prudent to investigate whether these ports are treated independently or have the capability to be aggregated together for a high-speed IP-SAN architecture and with built-in resiliency. When sizing, it is recommended to select a system that supports multiple SATA drives covering your current and future needs (plus 50%), significant amounts of system memory and cache memory and battery back-up for this memory.

Current hard drive technology explained A contemporary, dedicated storage solution should feature a high-performance, low-latency iSCSI storage system, with a highly integrated, reliable, multifunction ASIC for fully featured, integrated storage virtualisation. A separate dedicated management Ethernet port is also important for ensuring that performance is not impacted upon during management and configuration sessions. It is important that the data access scales over long distances, particularly for remote data replication and disaster recovery applications. Just like other areas of the IT industry, the hard disk drive market has undergone a huge change in recent years, a migration from existing established technologies such as ATA (Advanced Technology Attachment) /eIDE Enhanace Integrated Drive Electronics and SCSI (Small Computer Systems Interface) being replaced by their newer serial bretheren Serial ATA or SATA and Serial Attached SCSI or SAS.

Both are storage interfaces or connections to enable peripherals such as hard disk drives to connect to a computer. In fact SATA has now replaced the old 16-bit ATA/EIDE technology on most computer motherboards; it has also become the de facto standard for dedicated storage for the desktop market. It is both significantly faster than the previous ATA standard and more efficiently packaged, as well as in operation, being full-duplex in nature. Hot-swapping or hot plugging is also standard with SATA drives, making it far easier to build-in redundancy. Serial Attached SCSI has all the benefits of the SATA along with the fact that SAS drives are rated for a higher duty cycle and therefore are traditionally used in high transaction environments. In terms of interface, both Serial technologies have the same interface enabling some enclosures to support both types of drives concurrently.

In terms of performance, both SAS and SATA support data rates and transfer rates of up to 6Gbps per device. In practise most solutions now support what have become known as the SATA I and SATA II standards, the former supporting up to 1.5Gbps and the latter up to 3Gbps. The next step is third generation SATA, or SATA III, supporting up to 6Gbps performance. While traditional hard disk technology is short of being able to fully take advantage of such a performance leap, caching will ensure that data reads are faster than before, while related technologies such as solid state disk drives will definitely benefit from the faster SATA standards. Therefore, legacy disk drive technology is not a performance issue as faster standards emerge.

Real world networking guide | Storage for SMBs

The need for more and more dedicated storage – The new wave of applications

NVRs defined

The demand for data storage has been made all the greater as a result of the new wave of data hungry applications that are now becoming commonplace.

Within IP surveillance, specialist storage capture and replay devices such as NVRs (Network Video Recorders) are an essential component. For all kinds of video applications, the NVR removes the need for PCs to store data, so that events, training and other video recordings can be centrally stored and made available online at any time, with the video delivery completely under the control of the user. General network storage is also available with video streaming capabilities.

In addition to specialist markets such as digital media – music publishing, film and video editing etc – new kinds of mainstream applications are requiring terabytes of storage to be made available, online, at all times. Application: Storage as a Service Storage as a Service – not to be confused with Software as a Service (SaaS) is a business model whereby a company creates a single storage infrastructure pool, which it then carves up and shares throughout the company on a per use/capacity model, much in the same way that traditional mainframe computers were time-shared in the ‘70s and ‘80s. From a company management perspective this is attractive since it moves the IT infrastructure from being a CapEx to an OpEx Cost allowing for simpler cash flow management. The negative with this model is that it costs you more over time, plus you have to accept what you’re given as opposed to buying what you want. Also, the other challenge for this model is that Internet connection speeds across Europe vary considerably which means that network bandwidth can become an issue.

For example, Storage as a Service is a convenient way to store and manage backups for DR purposes, and this makes a huge amount of sense for SMBs. The key advantage is in cost savings, both in terms of hardware and personnel, as well as physical storage space – often at a premium nowadays. Storage as a Service can effectively decrease the size of a tape library, providing a secure backup to the main storage facility within your own company. Typically, service level agreements (SLAs) can be made with the remote storage service provider, in the unlikely event of the service being unavailable or, worse still, data loss or corruption. As such, Storage as a Service is being promoted as a way for SMBs to enhance business data continuity and availability by providing risk mitigation in disaster recovery and securing long-term data retention. Application: IP Surveillance IP surveillance is becoming an increasingly important application for SMBs, not simply as a cost-effective and easily managed alternative to traditional CCTV, but – because of its flexibility – the basic components, such as hi-resolution IP cameras, can be used in many different kinds of applications such as Internet conferencing and training. Regardless of the exact application, the important point to bear in mind is that when recording from these devices, the amount of data being generated is huge. So integrating with a scalable storage solution is essential to be able to match that data generation to that of the IP cameras being used.

Application: Image backups for PCs. While not an everyday occurrence, failures on PCs and laptops where they are unable to boot up, due to either disk drive failure or data corruption are not uncommon. Clearly, this can cause very serious problems for the user. Even if the data is backed up, there is still the issue of applications, some of which may be difficult to re-install, and indeed the whole issue of creating effectively a “new” PC from scratch. The answer is to store an image of that PC – this is the complete operating system, data and applications – on a dedicated storage facility so, in the event of such a failure, the user is able to be brought fully back online as quickly as possible. Given the size of a typical PC or laptop image, there is no alternative here but to use dedicated storage. Security is also a very important consideration here too as there is a potentially significant security issue if those images are able to be re-installed by, and in, the wrong hands. Effectively, it is like having your laptop stolen, so the only realistic method is to store PC images on secure, yet easily accessible, dedicated storage.

Application: Data Archiving Some information is more critical than others within a company, hence it must be protected and retained for access for long periods of time. As a result, a common methodology to address this problem is to create a data archiving routine/schedule, whereby after a certain length of time, or based on data/files not being accessed for a given period, or any similar criteria, that data is removed from the “front line” and archived on, traditionally, cheaper storage media. This is called hierarchical storage management or HSM for short. Mainly deployed within large organisations, it is designed to move infrequently used data to cheaper disk and tape storage. However this does not mean this methodology cannot be implemented in smaller organisations to great effect helping to reduce management and running costs. Commonly, data can be classified in one of three modes – online, near-line, or offline, the latter typically being a tape backup library. The problem with this approach is that tape media, unless it’s actively recycled, degrades overtime so backups cannot be guaranteed to be accessible when actually required and, equally, when an archived file is required. Often this is only discovered during an emergency, leading to financial penalties of some sort imposed or otherwise. Another drawback of this mode is that it is slow, since all the data needs to be parsed to enable retrieval of that one illusive file.

Now, thanks to the relative affordability of dedicated, networked storage, it is realistic to create a data archiving strategy completely based on hard-disk technology, even if that storage sits on a relatively low-speed networked connection (either local or remote) and makes that data available almost instantly as required. Application: IP Telephony Call Recording/ Internet Session Recording Although it may sound a bit “big brother”, in many instances now, the recording of calls, or even Internet activity – for example, Instant Messaging conversations – is not only useful, but invaluable in the case of identifying illegal activity and, in some cases, is mandatory from a legal perspective.

The problem with voice, video or user Internet session recording is that it requires very significant amounts of storage. Hence, it is unrealistic to just use local PCs to do this. Instead, dedicated storage is a far better solution, not simply because of the data storage requirements themselves, but also the security issues and ease of access when required to be replayed. As an alternative to traditional landline telephony, or even mobile, IP telephony, based on VoIP (Voice over IP) can make a lot of sense for an SMB in terms of reducing overall call costs, as well as adding additional features and flexibility. However, managing an IP Telephony system can generate significant amounts of data, especially if calls are being recorded and stored, making it, again, an ideal application for dedicated storage in this instance.

Real world networking guide | Storage for SMBs

In summary It is no longer realistic for an SMB to store data across standard PCs and servers, for the many and various reasons referenced in this guide.

To summarise, dedicated data storage has several key benefits, such as: • Controlled, secure access to data at all times, both locally and remotely, such as via the Internet. • High performance SAN/NAS systems mean that data is accessible at very high speeds, with zero impact on the users’ PCs or the application servers themselves. • Data storage requirements are increasing almost exponentially. Only dedicated storage solutions provide the levels of scalability and support for longer term capacity planning required to prevent SMBs running out of storage space. • In-built resilience and redundancy features to ensure 24x7x365 data availability to minimise – and almost completely remove – expensive data loss and downtime. • The storage can be located either locally or remotely, making it perfect for other applications such as data archiving and disaster recovery.

• Tiered, secure access methodologies mean that the administrator can tailor data access to suit their user base, with different types of users being given specific access rights to different sets of data, as required. • Data-hungry applications such as IP Surveillance are effectively impossible to support on a classic PC/server network without dedicated storage facilities, and require dedicated storage devices such as NVRs. Overall, the argument in favour of dedicated networked storage for any SMB is overwhelming. Providing secure, centralised data, accessible from anywhere, manageable from anywhere, with the proviso of ensuring minimal data loss, is an obvious benefit for any company and perhaps a life-saver. Add in key elements such as scalability, data redundancy and support for new wave applications such as IP surveillance and you have a future-proofed storage solution to confidently move forward with.

A guide to the D-Link storage solutions D-Link offers a wide variety of SAN, NAS and mixed-capability solutions that leverage the technologies and protocols already mentioned. We help organisations regain control of data and reduce exposure to data loss disaster. Our integrated solutions protect your intellectual property, enable instantaneous restores, and ensure business continuity. The products listed here offer flexible SAN and NAS network storage solutions. For more information, please visit

Storage Area Network (SAN)

Network Attached Storage (NAS)


The xStack DSN-1100-10 iSCSI Storage Array provides up to 10TB storage capacity for the SMB customer. It is ideally suited for workstations needing additional capacity or small businesses looking to consolidate or add extra storage capacity.


Single drive Network Storage Enclosure, using a single SATA drive, enables users to directly connect the DNS-313 to a computer via USB to transfer data and then connect directly to the LAN to share documents, photos and videos.


The xStack DSN-2100-10 iSCSI Storage Array is a rack mountable storage enclosure capable of providing up to 16TB storage capacity. Its 4xGbE ports add redundancy and throughput to any data intensive application.  


Two Drive Network Storage Enclosure, enabling users access to protect and share data files locally or over the Internet through the built-in secure FTP/SSL server. With integrated access, control specific users or groups can read or read/write to folder or files based on permission.


The xStack DSN-3200-10 iSCSI Storage Array adds up to 30TB storage capacity to your servers. It has eight 1GbE ports capable of being grouped together to increase bandwidth to 850MB/s for increased throughput and redundancy. 



The DSN-3400 implements the industry’s first fully integrated 10GbE interface, providing up to 1160MB/s bandwidth. It offers a high performance alternative to 4Gbps Fibre Channel for data intensive applications such as video editing and pre-press.

Four Drive Network Storage Enclosure adding enhanced RAID functionality and security. The DNS-343 boasts Microsoft Active Directory support as well as an officially licensed and integrated BitTorrent™ client.

Real worldnetworking guideStorage for SMBs  

Welcome to the latest in a series of real world networking guides from D-Link, written specifically for small business owners, managers and...