pt-ioprofilep - Online in the Cloud

PROGRAM:

NAME

pt-ioprofile - Watch process IO and print a table of file and I/O activity.

SYNOPSIS

Usage: pt-ioprofile [OPTIONS] [FILE]

pt-ioprofile does two things: 1) get lsof+strace for -s seconds, 2) aggregate the result.
If you specify a FILE, then step 1) is not performed.

RISKS

WARNING: pt-ioprofile freezes the server and may crash the process, or make it perform
badly after detaching, or leave it in a sleeping state! Before using this tool, please:

· Read the tool's documentation

· Review the tool's known "BUGS"

· Test the tool on a non-production server

· Backup your production server and verify the backups

pt-ioprofile should be considered an intrusive tool, and should not be used on
production servers unless you understand and accept the risks.

DESCRIPTION

pt-ioprofile uses "strace" and "lsof" to watch a process's IO and print out a table of
files and I/O activity. By default, it watches the mysqld process for 30 seconds. The
output is like:

Tue Dec 27 15:33:57 PST 2011
Tracing process ID 1833
total read write lseek ftruncate filename
0.000150 0.000029 0.000068 0.000038 0.000015 /tmp/ibBE5opS

You probably need to run this tool as root.

pt-ioprofile works by attaching "strace" to the process using "ptrace()", which will make
it run very slowly until "strace" detaches. In addition to freezing the server, there is
some risk of the process crashing or performing badly after "strace" detaches from it, or
of "strace" not detaching cleanly and leaving the process in a sleeping state. As a
result, this should be considered an intrusive tool, and should not be used on production
servers unless you are comfortable with that.

OPTIONS

--aggregate
short form: -a; type: string; default: sum

The aggregate function, either "sum" or "avg".

If sum, then each cell will contain the sum of the values in it. If avg, then each
cell will contain the average of the values in it.

--cell
short form: -c; type: string; default: times

The cell contents.

Valid values are:

VALUE CELLS CONTAIN
===== =======================
count Count of I/O operations
sizes Sizes of I/O operations
times I/O operation timing

--group-by
short form: -g; type: string; default: filename

The group-by item.

Valid values are:

VALUE GROUPING
===== ======================================
all Summarize into a single line of output
filename One line of output per filename
pid One line of output per process ID

--help
Print help and exit.

--profile-pid
short form: -p; type: int

The PID to profile, overrides "--profile-process".

--profile-process
short form: -b; type: string; default: mysqld

The process name to profile.

--run-time
type: int; default: 30

How long to profile.

--save-samples
type: string

Filename to save samples in; these can be used for later analysis.

--version
Print the tool's version and exit.

ENVIRONMENT

This tool does not use any environment variables.

SYSTEM REQUIREMENTS

This tool requires the Bourne shell (/bin/sh).

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