Determining performance in a distributed application or system

An automated sandbox deployed in a controlled cloud environment having a least part of the environment linked with a virtual infrastructure, the sandbox for monitoring problems associated with the treatment of a query instigated, in use, by a user, the sandbox comprising:

• a determination module for determining one or more nodes associated with the treatment of the query;
• a stimulus generating module for generating one or more stimuli associated with the treatment of the query wherein the or each stimulus are likely to perturb one or more resources within the system;
• a measurement device for measuring data at the or each node relating to the resources to determine the effect of the or each stimuli at the or each node;
• a correlation module for identifying one or more pairs of nodes which have a correlation in the measured data;
• and
• a model creation module for:
• transforming the correlation into a causal relationships where the cause is the measuring device directly measuring the stimulated resource and the consequences are the other correlated measuring devices;
• generating a list of causal relationships;
• combining different causal relationships into a causal model so that a chain of causal propagations can be built..