fsrw.d - file system read/write event tracing. Uses DTrace. fsrw.d This traces file related activity: system call reads and writes, vnode logical read and writes (fop), and disk I/O. It can be used to examine the behaviour of each I/O layer, from the syscall interface to what the disk is doing. Behaviour such as read-ahead, and max I/O size breakup can be observed. Since this uses DTrace, only the root user or users with the dtrace_kernel privilege can run this command. Solaris unstable - this script uses fbt provider probes which may change for future updates of the OS, invalidating this script. Please read Docs/Notes/ALLfbt_notes.txt for further details about these fbt scripts.

Trace file system read/write events, # fsrw.d

Event traced event (see EVENTS below)

Device device, for disk I/O

RW either Read or Write

Size size of I/O in bytes

Offset offset of I/O in kilobytes

Path path to file on disk

sc-read system call read

sc-write system call write

fop_read logical read

fop_write logical write

disk_io physical disk I/O

disk_ra physical disk I/O, read ahead

Richard McDougall, Solaris Internals 2nd Ed, FS Chapter.

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