bitesize.d - analyse disk I/O size by process. Uses DTrace. bitesize.d This produces a report for the size of disk events caused by processes. These are the disk events sent by the block I/O driver. If applications must use the disks, we generally prefer they do so sequentially with large I/O sizes, or larger "bites". Since this uses DTrace, only the root user or users with the dtrace_kernel privilege can run this command. Solaris stable - needs the io provider.

Sample until Ctrl-C is hit then print report, # bitesize.d

PID process ID

CMD command and argument list

value size in bytes

count number of I/O operations

The application may be requesting smaller sized operations, which are being rounded up to the nearest sector size or UFS block size. To analyse what the application is requesting, DTraceToolkit programs such as Proc/fddist may help.

See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs may include full worked examples with verbose descriptions explaining the output. bitesize.d will sample until Ctrl-C is hit. Brendan Gregg [Sydney, Australia] iosnoop(1M), seeksize(1M), dtrace(1M)