Once you gather the file I/O performance data, you can use it to adjust the system configuration to make the most efficient use of system resources.

If your database is using one file system on a striped volume, you may only need to pay attention to the file I/O activity statistics. If you have more than one file system, you may need to monitor volume I/O activity as well.

First, use the qiostat -r command to clear all existing statistics. After clearing the statistics, let the database run for a while during a typical database workload period. For example, if you are monitoring a database with many users, let the statistics accumulate for a few hours during prime working time before displaying the accumulated I/O statistics.

To display active file I/O statistics, use the qiostat command and specify an interval (using -i) for displaying the statistics for a period of time. This command displays a list of statistics such as:

											          OPERATIONS				 		FILE BLOCKS 								AVG TIME(ms)

	FILENAME									READ					WRITE	  	READ					WRITE 	 			READ					WRITE

	/db01/cust1							218		  				36	    872			 			144						22.8				 	55.6

	/db01/hist1									0				  		10		 				4				  	0.0					 10.0

	/db01/nord1								10				   	14	     40				   	56						21.0				 	75.0

	/db01/ord1									19				   	16	     76					   64						17.4				 	56.2

	/db01/ordl1							189						  41	    756						 164						21.1				 	50.0

	/db01/roll1									0					   50	      0					  200						 0.0				 	49.0

	/db01/stk1							1614						 238	   6456						 952						19.3				 	46.5

	/db01/sys1						 			0						  00				 		0					  0.0						 0.0

	/db01/temp1									0						  00					 	0					  0.0						 0.0

	/db01/ware1									3					   14	     12					   56						23.3				 	44.3

	/logs/log1										0						  00					 	0					  0.0						 0.0

	/logs/log2										0					  217	0		2255							0.0						 6.8

File I/O statistics help identify files with an unusually large number of operations or excessive read or write times. When this happens, try moving the "hot" files or busy file systems to different disks or changing the layout to balance the I/O load.

Mon May 11 16:21:20 2015

/db/dbfile01 														813 			 0 					813 						0    		0.3 			0.0

/db/dbfile02 														 	0		 813		 					0 			 813    		0.0 			5.5

Mon May 11 16:21:25 2015

/db/dbfile01 														816     0 		  	816 						0    		0.3 				0.0

/db/dbfile02 												 			0   816        0 													816   		0.0 				5.3

Mon May 11 16:21:30 2015

/db/dbfile01 												 			0     0        0 												  	0   	 0.0 				0.0

/db/dbfile02 												 			0     0        0 															0   	 0.0 				0.0