Hi Modugu --

I think you've got two questions.

First, do the lag warning and error thresholds need to be longer than the replication frequency of your relationship?  In other words, if you are mirroring once a day, can you set the lag warning threshold at one hour?  No, the lag measures how much time has elapsed since the last replication started, so just before the next scheduled update, the lag will be about 24 hours.  You'd want to set the lag threshold at something like 25 to 30 hours, depending on how long an update takes.

Second, do you need to acknowledge the events.  No, these events automatically reset themselves when the lag changes state.  So, if you have a lag warning and the relationship gets updated (so the lag now becomes much shorter), a "Lag OK" event will trigger and that automatically replaces the lag warning event as the "current" event for that relationship.  Many DFM events work like this.

-- Pete