Is there any connection between allowable data storage and test class failures while deploying a change set in production? I tried to deploy a change set which is creating some test data. It failed with some errors which can't be reproduced in sandboxes. When I check the Data Storage in System Overview I noticed that it has been exceeded. So I'm guessing it's the rout cause since it may unable to create test data. Is this the case or any other possible reasons?
The data storage will not be an issue when testing, the test data won't count against your data limits. Additionally the data storage is allowed to go over limit without affecting anything. However if you are surging over the limit you may need to purchase additional storage via your Salesforce sales rep. Best to have a conversation with them about the data storage limits. The issue lies with your code coverage and you have not successfully covered every eventuality of your code creating data, look to what extent your data will be creating records and try to replicate this directly in your test code.Test class code coverage
if you were creating data inside the test context the system would not consider the data storage quota as the records created inside test method never been persisted in the database. so it should be some other issues related with. so your issue is not related with data storage. it could be a heap limit when you trying to create large volume of test data inside a loop suppose to test a batch process. try to limit the record creation and try again.