Mongo vs cassandra: single point of failure

Question

In Cassandra vs Mongo debate, it is said that as mongo has master-slave architecture so it has a single point of failure(master) as when master fails, slave nodes take time to decide for new master, hence a window for downtime.

With Cassandra we don't have this problem as all nodes are equal. But then Cassandra too has a system wherein nodes use gossip protocol to keep themselves updated. In gossip protocol a minimum number of nodes are needed to take part. Suppose if one of the participating node goes down, then a new node needs to replace it. But it would take time to spawn a new replacement node, and this is a situation similar to master failure in mongo.

So what's the difference between 2 as far as single point of failure is concerned?

Answer 1

Also your assumptions about MongoDB are not correct.

Master-Slave replication has been removed in MongoDB version 4.0 (current version is 5.0), nowadays it uses Replica Sets

Typically you connect to a Replica Set rather than a single Replica Set member. When the current PRIMARY goes down, then a new PRIMARY will elected and your application will re-connect automatically and retries write operations to the new PRIMARY. It may hang for a few seconds but it should continue running.