iopattern(1m) [osx man page]
iopattern(1m) USER COMMANDS iopattern(1m) NAME
iopattern - print disk I/O pattern. Uses DTrace. SYNOPSIS
iopattern [-v] [-d device] [-f filename] [-m mount_point] [interval [count]] DESCRIPTION
This prints details on the I/O access pattern for the disks, such as percentage of events that were of a random or sequential nature. By default totals for all disks are printed. An event is considered random when the heads seek. This program prints the percentage of events that are random. The size of the seek is not measured - it's either random or not. Since this uses DTrace, only users with root privileges can run this command. OPTIONS
-v print timestamp, string -d device instance name to snoop (eg, dad0) -f filename full pathname of file to snoop -m mount_point mountpoint for filesystem to snoop EXAMPLES
Default output, print I/O summary every 1 second, # iopattern Print 10 second samples, # iopattern 10 Print 12 x 5 second samples, # iopattern 5 12 Snoop events on the root filesystem only, # iopattern -m / FIELDS
%RAN percentage of events of a random nature %SEQ percentage of events of a sequential nature COUNT number of I/O events MIN minimum I/O event size MAX maximum I/O event size AVG average I/O event size KR total kilobytes read during sample KW total kilobytes written during sample DEVICE device name MOUNT mount point FILE filename (basename) for I/O operation TIME timestamp, string IDEA
Ryan Matteson DOCUMENTATION
See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs may include full worked examples with ver- bose descriptions explaining the output. EXIT
iopattern will run forever until Ctrl-C is hit, or the specified count is reached. AUTHOR
Brendan Gregg [Sydney, Australia] SEE ALSO
iosnoop(1M), iotop(1M), dtrace(1M) version 0.70 Jul 25, 2005 iopattern(1m)
Check Out this Related Man Page
opensnoop(1m) USER COMMANDS opensnoop(1m) NAME
opensnoop - snoop file opens as they occur. Uses DTrace. SYNOPSIS
opensnoop [-a|-A|-ceghsvxZ] [-f pathname] [-n name] [-p PID] DESCRIPTION
opensnoop tracks file opens. As a process issues a file open, details such as UID, PID and pathname are printed out. The returned file descriptor is printed, a value of -1 indicates an error. This can be useful for troubleshooting to determine if applia- cions are attempting to open files that do not exist. Since this uses DTrace, only users with root privileges can run this command. OPTIONS
-a print all data -A dump all data, space delimited -c print current working directory of process -e print errno value -g print full command arguments -s print start time, us -v print start time, string -x only print failed opens -Z print zonename -f pathname file pathname to snoop -n name process name to snoop -p PID process ID to snoop EXAMPLES
Default output, print file opens by process as they occur, # opensnoop Print human readable timestamps, # opensnoop -v See error codes, # opensnoop -e Snoop this file only, # opensnoop -f /etc/passwd FIELDS
ZONE Zone name UID User ID PID Process ID PPID Parent Process ID FD File Descriptor (-1 is error) ERR errno value (see /usr/include/sys/errno.h) CWD current working directory of process PATH pathname for file open COMM command name for the process ARGS argument listing for the process TIME timestamp for the open event, us STRTIME timestamp for the open event, string DOCUMENTATION
See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs may include full worked examples with ver- bose descriptions explaining the output. EXIT
opensnoop will run forever until Ctrl-C is hit. BUGS
occasionally the pathname for the file open cannot be read and the following error will be seen, dtrace: error on enabled probe ID 6 (...): invalid address this is normal behaviour. AUTHOR
Brendan Gregg [Sydney, Australia] SEE ALSO
dtrace(1M), truss(1) version 1.60 Jan 12, 2006 opensnoop(1m)