Network Partitioning to tell if the other 3 servers have crashed or whether a network partition has isolated these 2 alone and therefore the group cannot be reconfigured automatically. On the other hand, if servers exit the group voluntarily, they instruct the group that it should reconfigure itself. In practice, this means that a server that is leaving tells others that it is going away. This means that other members can reconfigure the group properly, the consistency of the membership is maintained and the majority is recalculated. For example, in the above scenario of 5 servers where 3 leave at once, if the 3 leaving servers warn the group that they are leaving, one by one, then the membership is able to adjust itself from 5 to 2, and at the same time, securing quorum while that happens. Loss of quorum is by itself a side-effect of bad planning. Plan the group size for the number of expected failures (regardless whether they are consecutive, happen all at once or are sporadic). The following sections explain what to do if the system partitions in such a way that no quorum is automatically achieved by the servers in the group. A primary that has been excluded from a group after a majority loss followed by a reconfiguration can contain extra transactions that are not included in the new group. If this happens, the attempt to add back the excluded member from the group results in an error with the message  This member has more executed transactions than those present in the group. The  replication_group_members  performance schema table presents the status of each server in the current view from the perspective of this server. The majority of the time the system does not run into partitioning, and therefore the table shows information that is consistent across all servers in the group. In other words, the status of each server on this table is agreed by all in the current view. However, if there is network partitioning, and quorum is lost, then the table shows the status  UNREACHABLE  for those servers that it cannot contact. This information is exported by the local failure detector built into Group Replication. 3752 Detecting Partitions Tip Note