...... > > I have read that under Solaris one can use DTrace to get I/O request > size distribution on a global scale (also on a per process/pid basis). > See for example > > http://prefetch.net/articles/observeiodtk.html > > Can anyone recommend an alternative to get similar information under > CentOS? I looked into dtrace for linux but it seems still work in > progress, even putting aside CDDL issues ... > > http://www.crisp.demon.co.uk/tools.html > You can try SystemTap: http://sourceware.org/systemtap/ It seems to be roughly analagous to dtrace and is aimed squarly at the linux kernel.