iotop is a handy program that shows you real-time I/O usage in a format like the
top command. This should help you identify the script/binary thats doing all the I/O. I think this may already be installed on newer kernels, but yum may provide it on RHEL if you don't see it.
lsof is also helpful with I/O troubleshooting; it lists any open files.
If there is "constant" disk activity, then
iotop should tell you which process(es) are the culprits. Regarding I/O transaction history: I don't believe IO history is logged anywhere in most Linux distros, but you can add a cron job.
As root, open up crontab with
crontab -e and add these two lines:
* * * * * /bin/date >> /var/log/iotop; /usr/local/bin/iotop -bot --iter=3 -q >> /var/log/iotop
* * * * * /bin/date >> /var/log/lsof; /usr/bin/lsof -b -w >> /var/log/lsof
lsof output to a log every minute. Add a logrotate script for each to keep the files from taking up all your space, e.g.:
someuser@myhost:~> cat /etc/logrotate.d/lsof