We're having some trouble with SQL Server hosted on a virtual server. We occasionally have short periods where even performing a simple select takes minutes. During this period the CPU and memory usage on the server appear normal. We've performed some basic monitoring of the server using performance monitor but this hasn't uncovered anything and we're out of ideas. What would be the next step in diagnosing the problem?
The only signs of the problem we are seeing on the server are Event Log messages informing us that "SQL Server has encountered x occurrence(s) of I/O requests taking longer than 15 seconds to complete"