NAME

bitesize.d - analyse disk I/O size by process. Uses DTrace.

SYNOPSIS

bitesize.d

DESCRIPTION

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 users with root privileges can run this command.

EXAMPLES

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

FIELDS

PID: process ID
CMD: command and argument list
value: size in bytes
count: number of I/O operations

NOTES

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.

DOCUMENTATION

See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs may include full worked examples with verbose descriptions explaining the output.

EXIT

bitesize.d will sample until Ctrl-C is hit.

AUTHOR

Brendan Gregg [Sydney, Australia]