We have an issue where it looks like our site goes down temporarily (about 2 minutes) and the admin cannot publish (system i.o errors).  It appears to coincide with an indexing.  Does this examine run always and index on the fly as well as do a full index on a scheduled time too?   It looks like this is happening right around midnight and noon. If so, where would that setting be?   We are trying to find out why and see if we can adjust these schedules to resolve the issue.   Thanks for any info...