How do I perform a simple and rather naive benchmark of the disks seek and transfer performance under FreeBSD operating system? How do I perform a simple measurement of the I/O read command overhead for my RAID-1 array under FreeBSD operating systems?

You need to use the diskinfo command, which displays out information about a disk device, and optionally runs a naive performance test on the device. The -t option is used for a simple performance test.

Simple Measurement Of The I/O Read

The -c option triggers a simple measurement of the I/O read command overhead, enter:
# diskinfo -c /dev/aacd0
Sample Outputs:

/dev/aacd0
	512         	# sectorsize
	299573968896	# mediasize in bytes (279G)
	585105408   	# mediasize in sectors
	36421       	# Cylinders according to firmware.
	255         	# Heads according to firmware.
	63          	# Sectors according to firmware.

I/O command overhead:
	time to read 10MB block      0.062739 sec	=    0.003 msec/sector
	time to read 20480 sectors   1.169154 sec	=    0.057 msec/sector
	calculated command overhead			=    0.054 msec/sector

Simple Benchmark Of The Disks

The -t option triggers a simple and rather naive benchmark of the disks seek and transfer performance, enter:
# diskinfo -t /dev/aacd0
Sample Outputs:

/dev/aacd0
	512         	# sectorsize
	299573968896	# mediasize in bytes (279G)
	585105408   	# mediasize in sectors
	36421       	# Cylinders according to firmware.
	255         	# Heads according to firmware.
	63          	# Sectors according to firmware.

Seek times:
	Full stroke:	  250 iter in   0.724105 sec =    2.896 msec
	Half stroke:	  250 iter in   0.716784 sec =    2.867 msec
	Quarter stroke:	  500 iter in   2.109663 sec =    4.219 msec
	Short forward:	  400 iter in   1.621695 sec =    4.054 msec
	Short backward:	  400 iter in   1.624951 sec =    4.062 msec
	Seq outer:	 2048 iter in   0.119046 sec =    0.058 msec
	Seq inner:	 2048 iter in   0.217687 sec =    0.106 msec
Transfer rates:
	outside:       102400 kbytes in   0.649656 sec =   157622 kbytes/sec
	middle:        102400 kbytes in   0.523038 sec =   195779 kbytes/sec
	inside:        102400 kbytes in   0.745649 sec =   137330 kbytes/sec

Other Software

Bonnie++ Performance Test of Filesystem I/O : Bonnie tests the speed of file I/O using standard C library calls. It does reads and writes of blocks, testing for the limit of sustained data rate (usually limited by the drive or controller) and updates on a file (better simulating normal operating conditions and quite dependent on drive and OS optimisations).