I ported OpenTSDB to Accumulo this weekend: "OpenTSDB is a distributed, scalable Time Series Database (TSDB) written on top of HBase."
This evening I wrote a test client to generate fake data and my little laptop was able to store 100 points for 1000 servers every 10 seconds. It's a neat bit of software, and it was relatively easy to convert to Accumulo. http://github.com/ericnewton/opentsdb -Eric
