The Tombstones Per Read option displays the latest metrics for Tombstones and Live Cells scanned per read, for each column family, averaged across the cluster.
The Tombstone Mean column represents, on average, how many tombstones are read per read request.
The Tombstone Max column represents the highest number of tombstones read in a read request.
The Live Cells Mean column represents, on average, how many live cells are read per read request.
The Live Cells Max column represents the highest number of live cells read in a read request.
All values are calculated over roughly the last 5 minutes of activity.
High ratios of tombstones to live cells (greater than 5x as a starting guide) can cause substantially reduced performance in reads from a column family and suggest a need for a change in data model. Contact firstname.lastname@example.org if you need further assistance in dealing with tombstone issues.
The Tombstones Per Read option shows the mean and maximum tombstones and live cells read per read request.