Latch waits

-- Latch waits (SH and EX) indicate IO subsystem too busy the wait time indicates time waiting for disk
SELECT wait_type, waiting_tasks_count, wait_time_ms, signal_wait_time_ms,
    wait_time_ms - signal_wait_time_ms AS io_wait_time_ms
FROM sys.dm_os_wait_stats
WHERE wait_type LIKE 'PAGEIOLATCH%'
ORDER BY wait_type
GO