Keep Everything Forever, Part II - Indexing

In our last entry we reintroduced the idea of a keep everything forever storage retention strategy. We also touched on some of the basic capabilities like cost effective storage options and data movement options that can make a forever retention strategy realistic. In this entry we will look at what is one of the most important requirements the ability to find what you have in the archive.The fact that you have a keep it all retention strategy is going to be of little value to you if you can't find a discrete piece of information when you need it. Typically you are keeping all this data in case at some point down the road you need to produce it. Most often this will be in response to some sort of legal action or needing to prove adherence to a regulation. While you don't need rapid restore speed in these cases you do need to be able to deliver it in a timely manner. You can longer throw people at the problem and manually dig through information. In some cases you have to have a system in place that can not only find what you do have but also prove that you don't have something.

This comes down to implementing a solution that can index all the information that you have on storage and give you the ability to search on key words or phrases. I believe this index has to be storage vendor agnostic and potentially even device type agnostic. For example the ability that some backup applications have to build index information on the data that passes through it is good but the only thing being indexed is just that information that passes through the application. What about the data that does not get backed up by that application? Also what if you change your mind and switch applications? Are you really prepared to lock into a particular backup application for decades? And if you were do you think it is realistic to expect to send all your data through that application forever?

Beyond being storage and vendor agnostic the indexing system has to be able to scale to handle the ever growing amount of data that it will be responsible for. Scale here comes in two ways. The first is the ability to scale to meet ingestion rates. In other words how much information can the indexing system process in a given window? The other is how large can the meta-data that the indexing system creates scale to? If you are planning on keeping information forever that meta-data catalog's performance becomes critical.

The final piece also relates to the meta-data that the indexing system creates, how space efficient is the meta-data? You don't want to have to double your capacity requirements to hold all this meta-data, so the indexing system has to be able to capture the information it needs but do so very space efficiently.

Finding information in a keep it forever strategy is important, but probably most important is if you can actually afford to keep it forever. Our final entry in this series will cover trying to determine if a keep it forever strategy is cost effective.

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George Crump is lead analyst of Storage Switzerland, an IT analyst firm focused on the storage and virtualization segments. Find Storage Switzerland's disclosure statement here.