disable it....
chkconfig --levels 0123456 smartd off.
Alright, I'll let you decide first if you really want it or not, check out this link
http://kbase.redhat.com/faq/FAQ_85_3642.shtm
I don't use Dell's, but HP (which has it's own agents for pre-emptive failures), perhaps Dell has the same. Again, I haven't really looked into it much but smartd may not even support scsi drives all references seem to ide...although don't quote me on that.