The following syntax can be used to time how well write activities are occuring on a set of file systems (drives). In this test, I will create a 1GB file and time it:
# time dd if=/dev/zero of=/u03/test/large_file.dat ibs=1024 count=1048576 1048576+0 records in 2097152+0 records out real 0m33.086s user 0m2.340s sys 0m13.990s
# time sync real 0m2.674s user 0m0.000s sys 0m0.020s