| This graph shows average waiting time/latency for different categories of disk operations.   The times that include the queue times indicate how busy your system is.  If the waiting time hits 1 second then your I/O system is 100% busy. | 
		  
		    
		    
		    
		    
			  | Field | Internal name | Type | Warn | Crit | Info | 
		  
		    
		      | Device IO time | svctm | gauge |  |  | Average time an I/O takes on the block device not including any queue times, just the round trip time for the disk request. | 
		    
		  
		    
		      | IO Wait time | avgwait | gauge |  |  | Average wait time for an I/O from request start to finish (includes queue times et al) | 
		    
		  
		    
		      | Read IO Wait time | avgrdwait | gauge | 0:1 |  | Average wait time for a read I/O from request start to finish (includes queue times et al) | 
		    
		  
		    
		      | Write IO Wait time | avgwrwait | gauge | 0:1 |  | Average wait time for a write I/O from request start to finish (includes queue times et al) |