Accumulo is wonderfully scalable to address demands across many aspects of modern data needs.
What do you dislike?
In order to utilize Accumulo properly you must have substantial understanding of low level implementation details. Being able to properly design each of the elements of a row key and utilize techniques like server side iterators are a must for decent performance.
Recommendations to others considering the product:
Consider first if a simpler and more mature technology could meet your needs. If you truly have "big data" and need some of Accumulo's unique features it can be a great tool to use.
What problems are you solving with the product? What benefits have you realized?
I have utilized Accumulo to create a scalable unified data storage platform for analysis and visualization.
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