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BONNIE(1)              DragonFly General Commands Manual             BONNIE(1)


NAME

     bonnie - Performance Test of Filesystem I/O


SYNOPSIS

     bonnie [-d scratch-dir] [-s size-in-MB] [-m machine-label]


DESCRIPTION

     Bonnie tests the speed of file I/O from standard C library calls.  It
     reads and writes 8KB blocks to find the maximum sustained data rate
     (usually limited by the drive or controller) and additionally rewrites
     the file (better simulating normal operating conditions and quite
     dependent on drive and OS optimisations).

     The per character read and write tests are generally limited by CPU speed
     only on current generation hardware. It takes some 35 SPECint92 to read
     or write a file at a rate of 1MB/s using getc() and putc().

     The seek test results depend on the buffer cache size, since the fraction
     of disk blocks that fits into the buffer cache will be found without any
     disk operation and will contribute zero seek time samples.  (See BUGS
     below.)


OPTIONS

     -d scratch-dir
             Specify the directory where the test file gets written. The
             default is the current directory. Make sure there is sufficient
             free space available on the partition this directory resides in.

     -s size-in-MB
             Specify the size of the test file in MByte. This much space must
             be available for the tests to complete.

     -m machine-label
             Specify a label to be written in the first column of the result
             table.


SEE ALSO

     iozone(1), iostat(8)


AUTHOR

     Bonnie was written by Tim Bray <tbray@watsol.waterloo.edu>.


BUGS

     Bonnie tries hard to measure disk performance and not the quality of the
     buffer cache implementation. In merged buffer caches common today, the
     buffer cache size is often only limited by total RAM on an otherwise
     unloaded system. Be sure to use a file at least twice at large as
     available RAM to protect against artificially high results.

     There is no way to keep the buffer cache from increasing the reported
     seek rate. This is because the fraction of accesses corresponding to the
     amount of the file cached, will be done without seeks.  If your buffer
     cache is half the size of the file used, then half the requests will be
     satisfied immediately, and and the seek rate printed will be twice the
     actual value.

UNIX                             May 18, 1995                             UNIX

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