Contents
Is active replication better than passive replication?
Still active replication is the preferable choice when dealing with real time systems that require quick response even under the presence of faults or with systems that must handle byzantine faults. In passive replication there is only one server (called primary) that processes client requests.
What is replication differentiate between active and passive replication?
Unlike active replication, the passive replication distinguishes between a primary ob- ject which processes the requests, and the replicas which only receive updates from the primary. Therefore, the passive replication protocol must deliver the original message to the primary only, and send the updates to the backups.
What is mean by replication in distributed system?
Data replication is a method for organizing data storage whereby each data element is stored in several copies hosted on different servers. A distributed database is a data storage system consisting of local databases hosted on various nodes of a computer network. Every local database can have a replica.
What is replication and why is it important in statistics?
In statistics, replication is repetition of an experiment or observation in the same or similar conditions. Replication is important because it adds information about the reliability of the conclusions or estimates to be drawn from the data. The statistical methods that assess that reliability rely on replication.
How is passive replication used in a distributed system?
After processing a request, the primary server updates the state on the other (backup) servers and sends back the response to the client. If the primary server fails, one of the backup servers takes its place. Passive replication may be used even for non‐deterministic processes.
What are the disadvantages of active replication?
An atomic broadcast protocol guarantees that either all the servers receive a message or none, plus that they all receive messages in the same order. The big disadvantage for active replication is that in practice most of the real world servers are non‐deterministic.
How is a client request processed in active replication?
In active replication each client request is processed by all the servers. Active Replication was first introduced by Leslie Lamport under the name state machine replication. This requires that the process hosted by the servers is deterministic.
How is the front end of active replication?
Working of active replication: Request: The front end attaches a unique identifier to the request and multicasts it to the group of replica managers, using a totally ordered, reliable multicast primitive. The front end is assumed to fail by crashing at worst.