Over- or Under-size Your Backup Appliance on Purpose

When you're shopping for backup appliances, keep these four scalability parameters in mind.

By John Pearring, Manager of Sales, STORServer

Buying a backup appliance simplifies the entire integration effort, because you no longer worry about how the software and hardware work together. That's the good news. The bad news is that you still have a sizing decision to make, and picking the wrong sized solution can impact your success.

When shopping for backup appliances, get to know your own sizing issues before getting trapped with a solution that will not grow alongside your enterprise. Sales pitches from appliance manufacturers will include many enticing features, but the scalability of those appliances will likely determine the long-term success of your implementation.

Here are the four scalability parameters for appliances, followed by some factors that will help you determine the size for what you are trying to accomplish:

  1. Performance limits: How much data per day can a single appliance back up? This will dictate how many appliances are needed.

  2. Storage limits: How many terabytes can a single appliance back up? This determines the number of appliances needed from a multi-site perspective.

  3. Implementation limits: How many of the company's operating systems (Windows, Unix, etc.) and how much of the network and infrastructure (LAN, SAN, NAS, and WAN) can the solution actually back up? This helps defines the breadth of the appliance.

  4. Packaging limits: How many models are offered for an appliance from small to large, and how can you grow from one to the other or integrate these appliances? This determines the flexibility in your use of backup appliances to accomplish backup/archive/disaster recovery functions in your enterprise.

One way to look at the problem is to consider the "mistakes" that can be made from improperly over- or under-sizing your appliance. My suggestion is to take the positive side and decide purposely to go too big or too small. Your business will not stay the same size, so you can never be "just right." You might as well look at this as a matter of planning rather than avoidance.

The well-planned sizing answer comes from the following considerations.

Growth Calculations

How large is your company's data and subsequent backup/archive requirement? How far into the digital world does your industry now live? Practically everything can be digitized today, and the electronic conversion of previous hard-copy data has created enormous storage arrays in mid-market enterprises.

Although your retention policies will ultimately determine your backup requirement, it's safe to assume that three to six times the storage space is needed for a successful backup capture to ensure restores of all of your data, and another one to two times for archived information that will be stored for years. Obviously, the longer your restore requirements for backup and archived data, the more storage you will need.

Expansion Calculations

How quickly are your industry's data expectations growing? You should estimate at least 10 percent growth simply due to the typical increase in digitized information.

Industries and individual companies expand at separate rates. The faster an industry is growing, the more your data will likely expand. Even shrinking industries may be expanding digitally. For instance, U.S. banking's earnings per share (EPS) as an industry has been up and down, but lately shrinking over the past few years, and sales have been flat (according to analysis as of January 2011). Dividends, however, have remained positive.

The education and health-care sectors are typically leaders in growth and have continued steady expansion. Most industries, though, report continual increases in conversions of information to digital formats. Only you can estimate your own growth rates, regardless of how your industry is performing.

Locations and Mobility

Satellite offices and geographic expansions determine your location and mobility growth factors. Expansion can take place in both mergers and acquisitions and in establishing new office centers and operations. This factor can be the trickiest for backup/archive planning, not to mention the impact on disaster recovery (rebuilding a lost site from backup data).

Most obvious here is the rollout of appliances throughout the enterprise, where you decide which parts of the organization warrant a specific backup appliance investment. Not so obvious are those mobile users or smaller offices where you can consider the machines in play as simply an extension of a larger part of the enterprise.

The difficulty here is that some backup, archive, and disaster recovery planning does not consider individual users as part of the total data protection scheme. Dollars, however, are being spent here, so consider the opportunity to offer an "internal cloud" to your individual and mobile users, where they back up to your backup appliance. You retain ownership of the company's information and justify the total amount budgeted for to appliance purchases.

Rather than spend money on external hard drives or third-party backup vendors (showing up on expense reports all over the company), you can use the backup dollars already spent to justify your centralized appliance purchase. In fact, you will probably assure more disciplined backups for recovery, and address archive capabilities.

That said, you do need to ensure that your backup appliance choice can actually accomplish the internal cloud offering and also allow the flexibility of tying together all of your remote and local appliances in an effective and scalable way.

Backup appliances are designed to expand both capabilities and technologies into their architecture and implementation, while simplifying the finished product as it fits into increasingly complex environments. The configuration and quote experience counts toward a customer's decision making.

With this approach, you minimize making an over- or under-sizing decision. In fact, you may under-size an appliance purchase purposely because that appliance can be used elsewhere when the first implementation grows too large. You can also over-size an appliance successfully because you know that growth is coming at you rapidly, and you will save money and time with a ready-made solution for that growth.

The bad news turns into good news regarding sizing your appliance as long as you plan, and then purposely know what you are doing.

John Pearring is the manager of sales for STORServer. As the company's president from 1995 to 2008, John built the original OEM alliances and the original e-business infrastructure for the company. You can contact the author at

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