We present an approach and implementation for run-time correlation of large volumes of log data and symptom matching of know issues in the context of large enterprise applications. Our solution provides for (a) automatic data collection, (b) data normalisation into a common format, (c) run time correlation and analysis of the data to give a coherent view of system behaviour at run-time and (d) a symptom matching mechanism that can identify known errors in the correlated data on the fly. We have implemented our approach in the form of the Run-Time Correlation Engine (RTCE) and have applied it in a real industry test. Categories and Subject Descriptors D.2.5 [Testing and Debugging]: Diagnostics; C.4 [Performance of Systems]: Reliability, availability, and serviceability General Terms Performance, Reliability, Verification