You'll never love an appliance like your old database

Appliance trade-offs

Much depends both on what’s in the box, and what’s outside it. An appliance may capitalise on the simplicity of its management layer, which enables and means to get a lot done with little effort. But in many data centres that already have their own management layer, that may be a moot point. In fact, they may want more visibility into the box than an appliance’s management API can provide.

This highlights one of the underlying complexities of the database appliance market: vendors take different approaches to the architectural designs of their products. For example, Oracle’s database appliance is known to be “hard-wired”, in the sense that it is a hermetically sealed stack, lovingly tweaked to squeeze as much performance out of the components therein as possible. It is not designed to be broken up in any way.

Other appliances – from companies such as HP, Dell or SAP – don’t have the same level of hard-wiring, although they offer the same kinds of benefits in terms of convenience and simplicity. “The difference with those things is that you can actually break them up if you want to, because they are based on standard components, but you have the advantage that they are preconfigured,” Vile says.

The level of engineering in the box will dictate the level of performance you get, but there’s always a price trade-off. You’re paying for that convenience. 451’s Stamper says there’s a ceiling for performance in these appliances.

“While the appliance vendors will be more than happy to sell ever-larger appliances, that obviously comes at a cost,” he explains. “This is one of the reasons that many companies attempt to keep some of their data in a cheaper platform – most commonly Hadoop – in order to keep as much capacity on the appliance free as they can, and delay an expensive upgrade to a larger appliance.”

Sizing the workload

Part of the problem with a database appliance is that workloads don’t always stay the same. Computing demand tends to peak in relation to business demand, which can make it difficult to make full use of the power in an appliance, or conversely, may lead to situations in which demand exceeds the capability of the box.

For this reason, businesses interested in a database appliance might want to consider purchasing models that go beyond simple capex. With its database appliance, Oracle offers a pay-as-you-grow software licensing option, which lets them turn on processor cores on demand, without needing to upgrade the hardware. That can help solve the scalability problem for small to mid-sized businesses that may be on a high growth path.

Whether they’re tightly bound, or simply a collection of parts preconfigured to save an IT team the hassle, database appliances still have a common issue: they’re usually siloed. This can make it harder for a database appliance to be integrated with a broader infrastructure. A database appliance may be excellent and provisioning storage for a testing environment, for example, but all of the storage is still located in or attached directly to that box. The management layer rarely sees beyond that storage into the broader ecosystem.

Moreover, the database appliance is a single-function box that will only ever do database work, suggesting that this seems like an artificial place to stop.

“Why would you stop at the database? Look at an IBM PureSystem or any of the preconfigured cloud-in-a-box type offerings that any of the vendors have, and they give you a whole VMware layer or HyperV layer, so you’re dealing with everything up the stack,” Vile says. “So database appliances to me still look pretty niche.”