How to find out missing or deleted site collections in Staging Environment

We have created some 40+ site collections in staging environment.On the dev machines we used to development and deploy the wsps and run the powershell scripts in UAT to create site collections and sites.Yesterday when we started doing normal testing of our portal,we found that ROOT site colelction and another important site collection were missing.I checked the event viewer logs information in the UAT box.But did not find anything mysterious.Can anyone help how to find out why this happened?This happened within 12 hrs of time.If I enable Auditing on this SP Farm, will it help me to find what happened on those sites.I checked the content database of one missing sitecollection.Its intact.Later customer reported us that they faced some issues in their SAN storage environment.I am not able to find the link between these two.