Hi khkris,  Try: "every day every 4 hours between 12am and 11:59pm"  There is also a man page that helps with schedule syntax: man isi-schedule  Hope this helps!
I am trying to schedule a policy which run every 4 hours starting 12 AM to 11.59 PM.  I tried to use the examples from document but not succeeded.  Could any one help the syntax   Appreciate your help
Isilon Command help