Databases in the Cloud Revisited

A few of us were talking on Facebook about high speed rail (HSR) and where/when it makes sense the other day, and I finally said that it almost never does. Trains lost out to automobiles precisely because they are rigid and inflexible, while population densities and travel requirements are highly flexible. That hasn’t changed since the early 1900s, and isn’t likely to in the future, so we should be looking at different technologies to answer the problems that HSR tries to address. And since everything in my universe is inspiration for either blogging or gaming, this lead me to reconsider the state of cloud and the state of cloud databases in light of synergistic technologies (did I just use “synergistic technologies in a blog? Arrrggghhh…). There are several reasons why your organization might be looking to move out of a physical datacenter, or to have a backup datacenter that is completely virtual. Think of the disaster in Japan or hurricane Katrina. In both cases, having even the mission critical portions of your datacenter replicated to the cloud would keep your organization online while you recovered from all of the other very real issues such a disaster creates. In other cases, if you are a global organization, the cost of maintaining your own global infrastructure might well be more than utilizing a global cloud provider for many services… Though I’ve not checked, if I were CIO of a global organization today, I would be looking into it pretty closely, particularly since this option should continue to get more appealing as technology continues to catch up with hype. Today though, I’m going to revisit databases, because like trains, they are in one place, and are rigid. If you’ve ever played with database Continuous Data Protection or near-real-time replication, you know this particular technology area has issues that are only now starting to see technological resolution.

Over the last year, I have talked about cloud and remote databases a few times, talking about early options for cloud databases, and mentioning Oracle Goldengate – or praising Goldengate is probably more accurate.

Going to the west in the US? HSR is not an option.

The thing is that the options get a lot more interesting if you have Goldengate available. There are a ton of tools, both integral to database systems and third-party that allow you to encrypt data at rest these days, and while it is not the most efficient access method, it does make your data more protected. Add to this capability the functionality of Oracle Goldengate – or if you don’t need heterogeneous support, any of the various database replication technologies available from Oracle, Microsoft, and IBM, you can seamlessly move data to the cloud behind the scenes, without interfering with your existing database.

Yes, initial configuration of database replication will generally require work on the database server, but once configured, most of them run without interfering with the functionality of the primary database in any way – though if it is one that runs inside the RDBMS, remember that it will use up CPU cycles at the least, and most will work inside of a transaction so that they can insure transaction integrity on the target database, so know your solution. Running inside the primary transaction is not necessary, and for many uses may not even be desirable, so if you want your commits to happen rapidly, something like Goldengate that spawns a separate transaction for the replica are a good option… Just remember that you then need to pay attention to alerts from the replication tool so that you don’t end up with successful transactions on the primary not getting replicated because something goes wrong with the transaction on the secondary. But for DBAs, this is just an extension of their daily work, as long as someone is watching the logs.

With the advent of Goldengate, advanced database encryption technology, and products like our own BIG-IP WOM, you now have the ability to drive a replica of your database into the cloud. This is certainly a boon for backup purposes, but it also adds an interesting perspective to application mobility. You can turn on replication from your data center to the cloud or from cloud provider A to cloud provider B, then use VMotion to move your application VMS… And you’re off to a new location. If you think you’ll be moving frequently, this can all be configured ahead of time, so you can flick a switch and move applications at will.

You will, of course, have to weigh the impact of complete or near-complete database encryption against the benefits of cloud usage. Even if you use the adaptability of the cloud to speed encryption and decryption operations by distributing them over several instances, you’ll still have to pay for that CPU time, so there is a balancing act that needs some exploration before you’ll be certain this solution is a fit for you. And at this juncture, I don’t believe putting unencrypted corporate data of any kind into the cloud is a good idea. Every time I say that, it angers some cloud providers, but frankly, cloud being new and by definition shared resources, it is up to the provider to prove it is safe, not up to us to take their word for it. Until then, encryption is your friend, both going to/from the cloud and at rest in the cloud. I say the same thing about Cloud Storage Gateways, it is just a function of the current state of cloud technology, not some kind of unreasoning bias.

So the key then is to make sure your applications are ready to be moved. This is actually pretty easy in the world of portable VMs, since the entire VM will pick up and move. The only catch is that you need to make sure users can get to the application at the new location. There are a ton of Global DNS solutions like F5’s BIG-IP Global Traffic Manager that can get your users where they need to be, since your public-facing IPs will be changing when moving from organization to organization. Everything else should be set, since you can use internal IP addresses to communicate between your application VMs and database VMs. Utilizing a some form of in-flight encryption and some form of acceleration for your database replication will round out the solution architecture, and leave you with a road map that looks more like a highway map than an HSR map.

More flexible, more pervasive.

Published May 24, 2011
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