title: How to store historic time series data
body: <p>we're storing a bunch of time series data from several measurement devices.
  All devices may provide different dimensions (energy, temp, etc.)</p>
  
  <p>Currently we're using MySQL to store all this data in different tables (according to the dimension) in the format
    idDevice, DateTime, val1, val2, val3</p>
  
  <p>We're also aggregating this data from min -> Hour -> Day -> Month -> Year each time we insert new data</p>
  
  <p>This is running quite fine, but we're running out of disk space as we are growing and in general I doubt that a RDBMS is the right answer to keep archive data.</p>
  
  <p>So we're thinking of moving old/cold data on Amazon S3 and write some fancy getter that can recieve this data.</p>
  
  <p>So here my question comes: what could be a good data format to support the following needs:</p>
  
  <p>The data must be extensible in terms: once i a while a device will provide more data, then in the past -> the count of rows can grow/increase</p>
  
  <p>The data must be updated. When a customer delivers historic data, we need to be able to update that for the past.</p>
  
  <p>We're using PHP -> would be nice to have connectors/classes :)</p>
  
  <p>I've had a look on HDF5, but it seems there is no PHP lib.
  We're also willing to have a look on cloud based TimeSeries Databases.</p>
  
  <p>Thank you in advance!
  B</p>