BONNIE(1) BSD General Commands Manual BONNIE(1)NAMEbonnie — Performance Test of Filesystem I/O
SYNOPSISbonnie [-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 (usu‐
ally 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 ALSOiozone(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 avail‐
able 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
