title: How to store audit data in Azure
body: <p>We're in the design phase for building an audit trail in an existing web application. The application runs on Windows Azure and uses a SQL Azure database. </p>
  
  <p>The audit logs must be filtered by user, or by object type (eg. show all action of a user, or show all actions that are performed on a object). </p>
  
  <p>We have to choose how to store the data, should we use SQL Azure, or should we use table storage? We prefer table storage (cheaper)..</p>
  
  <p>however the 'problem' with table storage is how to define the partition key. We have several thousand customers (the appplication users) in our SQL database, each in their own tenant. Using the tenant ID as partition key is not specific enough, so we have to add something to the partition key. So there's the issue: given the requirements for filtering, we can add a user ID to the partition key to make filtering by user easy, or we can add an object ID to make filtering by object easy. </p>
  
  <p>So we see two possible solutions:<br>
  - use SQL Azure instead of table storage<br>
  - use table storage and use two tables with different partition keys, which means we duplicate all entries   </p>
  
  <p>Any ideas what's the best approach for our situation? Are there other, better solutions? </p>