There was a time when the only storage a small business required was a filing cabinet and the odd cardboard box or two. But increasing reliance on electronic data processing has seen demand for fast, reliable and secure storage, mostly magnetic disk, grow exponentially in recent years. Moreover, as companies strive to cope with ever more stringent data protection and compliance legislation, that trend looks set to continue.
This issue we’re looking at two related issues. The first is the different types of storage technologies and products available to the small-business buyer. The second is the issue of compliance, where we look at some of the more important pieces of legislation that small businesses need to get to grips with. These are not the high-profile international accords, such as Sarbannes-Oxley or Basel II, about which you will find a lot written elsewhere, but the more mundane requirements of the Data Protection Act and the European Privacy and Electronic Communications directive. These may not receive the same press coverage as the others, but they are important nevertheless, and need to be complied with.
We will look at compliance later, along with a couple of other storage-related topics, including the thorny subject of backup. Let’s start, though, by splitting storage technologies and products into three main types: direct-attached storage (DAS); network-attached storage (NAS); and the storage area network (SAN). Here we will explain the pros and cons of each for your small business.
Direct-attached storage
As the name suggests, direct-attached storage is where disks and other storage devices are connected directly to a host PC or server, for example, the internal drives in a system. As far as businesses are concerned, however, server attachment is the more important, and users should be encouraged – or even, some would say, compelled – to save all their work on shared network servers rather than their local hard disks. That way the information can be centrally managed and protected, rather than leaving users to ensure backups are taken, notebooks securely locked away and so on.
In terms of the technology there is nothing particularly special about server hard disks. They just need to be bigger, faster and, as much as possible, more reliable than those employed in desktop and notebook PCs. SCSI was once the technology of choice here, and still is on high-end systems. But in the small-business arena it’s rapidly being overtaken by serial ATA (SATA), which offers similar levels of capacity, performance and availability at a more affordable price.
Many businesses start with DAS, mainly because it’s relatively easy to understand and manage using the disk management software built into Windows, Novell Netware and virtually every Linux distribution available.
However, if you’re running a Windows server there’s a cost involved with this type of storage, as each user is required to have a Client Access Licence to connect to shares on the file server. One way of avoiding licensing costs is to use Linux servers running Samba, an application that uses the same Server Message Block (SMB) protocol as a Windows server but, because it’s open source, doesn’t need any client licences.
Servers with internal, or even externally attached disks can also be a headache if you start to run out of space. Adding hard disks isn’t costly but installing them while preserving your existing data can be very time-consuming and, of course, there is the overhead of running a server in the first place. If you need a server to host your email, run a database or an intranet website, this is not a problem. But, if not, there are cheaper and easier alternatives worth looking into, one of the most popular of which is network-attached storage.
Network-attached storage
With NAS, storage is connected directly to the network infrastructure rather than to a host server. Of course, this is not quite true, as a server is still required to share out the data. However, it doesn’t have to be a large general-purpose server running an operating system such as Windows. Instead it can be implemented in the form of a single board or even a chip inside a self-contained appliance, so that, effectively, the disks plug into the LAN network.
NAS appliances come in a range of shapes and sizes, from small single-disk devices, such as the Buffalo Linkstation Pro, to much larger appliances offering terabytes of storage, often with Raid (see panel) and hot-swap capabilities. Most will be Linux-based, which means there are no client licensing issues, though appliances running Windows Storage Server 2003 are available.
Deployment is much the same regardless of size or format. In most cases all you do is plug the appliance into the network and spend a few minutes configuring the required network shares, typically via a web interface. Windows users can then browse to those shares or connect using standard Windows drive mappings, just as they would if using a general-purpose server.
Some NAS appliances support other network protocols and operating systems, enabling the storage to be shared by Mac, Unix and Linux users as well as those with Windows PCs. One example is the Snap Server appliances from Adaptec, which can be used to share data on a wide range of networks. They are available in a range of capacities and formats, from the 80Gb Snap Server 1100 to the top-of-the-range Snap Server 550, which is based on a 64-bit AMD Opteron server platform, sporting up to 43.2Tb of Raid-protected storage in an easy-to-deploy NAS format.
Similar products are available from Dell, HP, IBM and others; most of the vendors also offer our third type of storage technology – the storage area network (SAN).
Storage area networks
Often confused with NAS, the SAN is, in fact, something quite different. To begin with, rather than attach the storage to the shared Ethernet LAN, on a SAN the storage is connected to a dedicated network of its own. And, instead of SMB and other network file-sharing protocols, SANs use block I/O protocols, such as those used to access DAS, which are both faster and more reliable.
SANs are mostly used to connect storage to servers rather than individual desktops, and are typically combined with management and virtualisation software which enables disks to be added and storage allocated to servers and applications on-the-fly, making for a fast and very flexible solution.
Two underlying networking technologies are used in SANs: either Fibre Channel or, more recently, iSCSI. Functionally, the two are similar and there’s little to choose between them in terms of performance. However, Fibre Channel requires special hubs, switches and adapters, whereas iSCSI SANs can be implemented using ordinary Ethernet hardware for the most part.
The development of iSCSI has made the SAN a much more affordable proposition, but even so it’s not right for every small business. Despite falling prices, a SAN is still a significant investment both in terms of the hardware involved and the additional management software required to take full advantage of what the technology can offer. If you have several servers and a need for lots of storage then a SAN could be worth considering, but otherwise it’s best to stick with DAS/NAS.
Don’t forget to back up
No matter what sort of storage you have, it needs to be protected by a workable backup regime. That means regular backups, off-site storage of the backup media, and a tried and tested procedure both for recovering accidentally deleted files and restoring complete systems in the event of a hardware or software failure.
Tape hardware remains a good choice for backups, as it’s a mature technology and well-supported by backup software vendors. However, compared with disk, tape drives can be slow and expensive – even those aimed specifically at small businesses. And if you have a large amount of data to protect it may not all fit on one tape, calling for an auto-loader or tape library to swap cartridges in and out under software control, which means yet more expense and complexity.
Where small amounts of data are involved, CD ROM and DVD recorders are a good alternative, otherwise small-business buyers should look at hard disk solutions, such as the Storcase Data Express, which offers up to 500Gb of fast SATA (serial ATA) disk space in a convenient removable disk format.
Of course you will also need backup software. Server editions of Windows come with a bundled utility, but it’s fairly basic. For full protection of servers, NAS appliances and workstations you will need to look at custom backup products such as EMC Retrospect or an open-source application such as Amanda (www.amanda.org) which can be used to protect network Windows and Linux servers.
Privacy and Electronic Communications directive
Like the Data Protection Act, the European Privacy and Electronic Communications Directive (2003) is all about ensuring privacy. It calls for anyone using electronic communications for marketing to adhere to two strict rules designed to tackle problems associated with bulk mailing and spam.
The first applies to all marketing messages regardless of recipient, requiring the sender to make their identity known and to provide a valid address for opt-out requests. The second applies to unsolicited marketing messages sent to individuals and is much stricter, barring such communications except where senders have the recipient’s consent – so-called ‘opt-in’ marketing.
This second rule can only be relaxed when three criteria are satisfied:
1. The recipient’s details are obtained ‘in the course of a sale or negotiations for a sale’.
2. Subsequent messages relate to ‘similar products and services’.
3. The recipient had the opportunity to opt out when their data was collected and is provided with that opportunity in every subsequent exchange.
The Privacy and Electronic Communications legislation is also designed to protect the privacy of individuals using ecommerce and other websites. In particular, it governs the type of information that can be collected and managed using cookies and other electronic means, with similar opt-in measures required.
Data collected before the directive came into force can continue to be used, but restrictions apply.A little bit of Raid
Storage performance and reliability can be enhanced using Raid (Redundant Array of Inexpensive Disks), where data is distributed or striped across two or more disks in an array, rather than stored on just one drive at a time.
The performance boost comes from being able to write to and read from several disks at the same time. Reliability is enhanced by adding parity and error-checking and correction (ECC) information so that – should one of the disks fail – any missing data can be rebuilt. For the highest levels of fault tolerance a specialised Raid controller is required, which adds support for hot-swapping of disks and hot-sparing, where disks are kept on standby in case a failure occurs.
The benefits of Raid depend on the type or level implemented (see table), with Raid levels 0, 1 and 5 the most popular configurations. The table explains the different options and how they compare.
Rev gains momentum
Iomega has a long history of providing storage technology for the small office – going right back to the legendary Zip disk drive. Now it’s banking on REV – a springloaded drive that offers a choice of 35Gb or 70Gb capcities.
Conventional hard drives are hermetically sealed; dust can’t get in to mess up the works. That’s why they’re fast, reliable, and have huge capacities. But it’s also why you can’t take the disk platter out of one drive and put it in another.
Iomega says it has designed the Rev drive to stay clean without sacrificing the capability to remove it from its box. The shutter on the drive and the shutter on the cartridge open in tandem, so the sealed environments of the read/write heads remain clean inside the drive. They also get cleaned automatically. An air filtration system emulates the clean environment of a conventional hard drive.
The drive uses the same error correction system – UDF 1.02 – as optical drives, though it’s an older version of UDF. Iomega is using this version because a variety of operating systems contain native UDF 1.02 readers, which helps make the Rev highly compatible, say company representatives. You can plug and play a Rev device somewhere that doesn’t have a UDF reader, and you’d still be able to read the data, but not write to it.
According to Iomega, the result is an extremely reliable drive, with an error rate that representatives say is “three orders of magnitude” better than standard hard drives. And although the Rev is not as fast as a hard drive, Iomega reports an average transfer rate of about 20 megabytes per second. That’s in the neighborhood of the fastest DVD drives, and much faster than tape drives.
And tape is the technology Iomega wants to replace. The Rev is designed for users who now rely on or are considering tape as their backup medium. Iomega says the Rev handles the job because it, too, is a back-up medium with a capacity larger than a DVD, and is more reliably portable than USB hard drives.
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