Replication and mirroring are terms that are often used interchangeably. But, they are not synonyms. They refer to similar, but not same technologies.
Replication is the process of making a copy of the original data in a geographically remote server. All read write operations happen on the primary data first and then the copy is incremented or differentially updated. The replication can be synchronous or asynchronous. The copy of the data can be used if the primary data becomes unavailable for some reason.
Mirroring is an ongoing process. The primary data store and the secondary data store are located on geographically distant servers as in replication but, read/write happens simultaneously on both the primary and the secondary data stores. The mirroring process is always synchronous and the two copies of the data are always in synchronization. Both servers are connected over a LAN or WAN. The secondary store will continue to service the needs of the customer if the primary store fails for some reason or vice versa.
The use of either of these techniques ensures high availability of data to the end user. Cloud service providers may use one or both these techniques to fulfill the promise of 99.9% uptime to their customers in the service level agreement (SLA). However, experts have listed some types of usage scenarios for replication and mirroring:
- When offline-online synchronization is the need—replication is the ideal technology. This is especially true in instances where a large number of mobile devices such as laptops, iPhone, iPads etc connect to the network to upload information or download data.
- When the enterprise has to remain always connected and continuous backup of data is an imperative, mirroring is the best option. Failover clustering options can be explored. Switchover from one server to the other can be made automatic and seamless and data losses can be minimized.
- If manual switchover from one server to another in the event of primary server failure is not a problem and continuous backup is not a business requirement, replication may be an option.
- If workload has to be spread across servers, replication is advocated.
Users exploring Cloud computing options will have to match their needs with the technologies offered by the service providers to get optimum benefits from their choices.
Securstore is here to help you with your replication and/or mirroring needs. Please contact us for a free, no obligation consultation.