Explanation

When a load test is executed from the local machine the assemblies required to run the test are copied to the controller. The files are copied to a directory on the controller in the following location Drive:\Users\[USER]\AppData\Local\VSEQT\QTController.The Test results are copied to a directory on the controller in the following location Drive:\Users\<Account>\AppData\Local\VSEQT\QTController\TestRunStorage.
Each deployment and TestRunStorage will have a further directory named with a unique GUID where the files are copied.

For example

Deployment folder location: C:\Users\[USER ACCOUNT]\AppData\Local\VSEQT\QTController\[GUID]
TestRunStorage folder location : C:\Users\[USER ACCOUNT]\AppData\Local\VSEQT\QTController\TestRunStorage\[GUID]

Workaround

Delete the folders under C:\Users\[USER ACCOUNT]\AppData\Local\VSEQT\QTController\. or a scheduled task to delete the folders periodically

Problem

The load test rig database was configured on SQL Server 2008 express edition which can hold maximum database size of 4 gb

Workaround

Note: Always test the blog script on your test environment before executing on production environment

This problem can be overcame by removing historical results

-- Start Script

-- This script deletes all load test run older than two weeks
-- To change the timeframe, change the number of days from 14 to the desired number
 
USE LoadTest
DECLARE @LoadTestRunId int
DECLARE OldLoadTestsCursor CURSOR FOR
    SELECT LoadTestRunId FROM LoadTestRun WHERE datediff(dd, StartTime, getdate()) > 14
 
OPEN OldLoadTestsCursor
FETCH NEXT FROM OldLoadTestsCursor INTO @LoadTestRunId
 
WHILE @@FETCH_STATUS = 0
BEGIN
    EXEC Prc_DeleteLoadTestRun @LoadTestRunId
    FETCH NEXT FROM OldLoadTestsCursor INTO @LoadTestRunId
END
 
CLOSE OldLoadTestsCursor
DEALLOCATE OldLoadTestsCursor

-- End Script

Script Reference :  http://blogs.msdn.com/b/billbar/archive/2006/02/09/528900.aspx

Solution

Configure the rig to other editions of SQL server.

Group Name: TeamTestAgentService

This group contains the minimal permissions needed for a test agent to connect to a test controller.Connect to a test controller
Before you configure a test agent, add the user accounts that you will use to run the test agent service. This is the user account that you specify in the Test Agent Configuration Tool when you install a test agent.

Group Name: TeamTestControllerUsers

Includes permissions from the TeamTestAgentService group.Start test runs.View test results
Add users that only need to run tests and view test results.

Group Name: TeamTestControllerAdmins

Includes permissions from the TeamTestControllerUsers and TeamTestAgentService groups.Delete, pause, or postpone any test run.Add, remove, and change the status of test agents.Create lab environments.
Before you configure a test agent, add the user accounts that you will use to run the test agent service. This is the user account that you specify in the Test Agent Configuration Tool when you install a test agent.