Replication in Cloud Computing refers to multiple storage of the same data to several different locations by usually synchronization of these data sources. Replication in Cloud Computing is partly done for backup and on the other hand to reduce response times, especially for reading data requests.
Replication in Cloud Computing : Basics
The simplest form of data replication in cloud computing environment is to store a copy of a file ( copy ), in expanded form, the copying and pasting in any modern operating systems. Replication is the reproduction of the original data in unchanged form. Changing data accesses are expensive in general through replication. In the frequently encountered master / slave replication, a distinction between the original data (primary data) and the dependent copies. In peer copies ( version control ) there must be merging of data sets (synchronization). Sometimes it is important to know which data sets must have the replicas. Depending on the type of replication it is located between the processing and creation of the primary data and their replication in a certain period of time. This period is usually referred to as latency.
Replication in Cloud Computing
Synchronous replication is when a change of operation can only be completed successfully on a data object, if it was performed on the replicas. In order to implement this technology, a protocol ensures the indivisibility of transactions, the commit protocol.
If between the processing of the primary data and the replication there is latency, it speaks of asynchrony. The data are identical. A simple variant of the asynchronous replication is the “File Transfer Replication”, the transfer of files via FTP or SSH. The data of the replicas make only a snapshot of the primary data at a specific time. At the database level this can happen in short time intervals, the transaction databases are transported from one server to another and read into the database. Assuming an intact network latency it corresponds to the time interval in which the transaction logs are written. Four methods can be used for Replication in Cloud Computing – Merge Replication, Primary Copy, Snapshot replication, Standby replication.