.TH iopending 1m "Nov 01, 2005" "version 0.60" "USER COMMANDS" .SH NAME iopending \- plot number of pending disk events. Uses DTrace. .SH SYNOPSIS .B iopending [\-c] [\-d device] [\-f filename] [\-m mount_point] [interval [count]] .SH DESCRIPTION This samples the number of disk events that are pending and plots a distribution graph. By doing this the "serialness" or "parallelness" of disk behaviour can be distinguished. A high occurance of a pending value of more than 1 is an indication of saturation. Since this uses DTrace, only users with root privileges can run this command. .SH OPTIONS .TP \-c clear screen .TP \-d device instance name to snoop (eg, dad0) .TP \-f filename full pathname of file to snoop .TP \-m mount_point mountpoint for filesystem to snoop .SH EXAMPLES .TP Default output, print I/O summary every 1 second, # .B iopending .PP .TP Print 10 second samples, # .B iopending 10 .PP .TP Print 12 x 5 second samples, # .B iopending 5 12 .PP .TP Snoop events on the root filesystem only, # .B iopending \-m / .PP .SH FIELDS .TP value number of pending events, 0 == idle .TP count number of samples @ 1000 Hz .TP load 1 min load average .TP disk_r total disk read Kb for sample .TP disk_w total disk write Kb for sample .PP .SH IDEA Dr Rex di Bona .PP .SH 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. .SH EXIT iopending will run forever until Ctrl\-C is hit, or the specified count is reached. .SH AUTHOR Brendan Gregg [Sydney, Australia] .SH SEE ALSO iosnoop(1M), iotop(1M), dtrace(1M)