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Timing Read and Write Functions in UNIX

by Jeff Hunter, Sr. Database Administrator

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