09-09-2008
iowait means the process is wating to complete an I/O and another process is ahead of it, or the I/O takes a while to complete. It is symptomatic of either poor programming or insufficient memory.
If you happen have RH running a P4 processor there is a known problem with iowait under certain confgurations. search their website for iowait.
This can usually be fixed for RH by updating to the latest kernel and/or putting the following lines into your /etc/rc.d/rc.local file:
echo 100 > /proc/sys/vm/inactive_clean_percent
echo 2 10 20 > /proc/sys/vm/pagecache
DO NOT DO THIS until you are certain what is going on.
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LEARN ABOUT CENTOS
trace-cmd-listen
TRACE-CMD-LISTEN(1) TRACE-CMD-LISTEN(1)
NAME
trace-cmd-listen - listen for incoming connection to record tracing.
SYNOPSIS
trace-cmd listen -p port [OPTIONS]
DESCRIPTION
The trace-cmd(1) listen sets up a port to listen to waiting for connections from other hosts that run trace-cmd-record(1) with the -N
option. When a connection is made, and the remote host sends data, it will create a file called trace.HOST:PORT.dat. Where HOST is the name
of the remote host, and PORT is the port that the remote host used to connect with.
OPTIONS
-p port
This option will specify the port to listen to.
-D
This options causes trace-cmd listen to go into a daemon mode and run in the background.
-d dir
This option specifies a directory to write the data files into.
-o filename
This option overrides the default trace in the trace.HOST:PORT.dat that is created when a remote host connects.
-l filename
This option writes the output messages to a log file instead of standard output.
SEE ALSO
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1), trace-cmd-stop(1), trace-cmd-extract(1), trace-cmd-reset(1),
trace-cmd-split(1), trace-cmd-list(1)
AUTHOR
Written by Steven Rostedt, <rostedt@goodmis.org[1]>
RESOURCES
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
COPYING
Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).
NOTES
1. rostedt@goodmis.org
mailto:rostedt@goodmis.org
06/11/2014 TRACE-CMD-LISTEN(1)