fddist - file descriptor usage distributions. Uses DTrace. fddist [-r|-w] This prints distributions for read and write events by file descriptor, by process. This can be used to determine which file descriptor a process is doing the most I/O with. Since this uses DTrace, only the root user or users with the dtrace_kernel privilege can run this command. Solaris stable - needs the syscall provider.

-r reads only

-w writes only

Sample both read and write activity, # fddist

Sample reads only, # fddist -r

EXEC process name

PID process ID

value file descriptor

count number of events

/usr/demo/dtrace/lquantize.d

DTrace Guide "Aggregations" chapter (docs.oracle.com) See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs may include full worked examples with verbose descriptions explaining the output. fddist will sample until Ctrl-C is hit. dtrace(1M)