We are thinking through the deployment architecture for our Cassandra cluster.  Let us say that we choose to deploy data across three racks.

If let us say that one rack power went down for 10 mins and then it came back. As soon as it came back up, due to some human error, rack1 goes down. Now for some rows it is possible that Quorum cannot be established. Just to minimize the issues, we are thinking of running read repair manually every night.

Is this a good idea? How often do you perform read repair on your cluster?