Replication

'''Replication''' in computer science refers to the creation and the use of redundant resources, such as 
software or hardware components, to improve availability, reliability, [[Fault Tolerance|fault tolerance]], or performance. 
Replication typically involves replication in space, in which the same application or data is stored on multiple 
file systems or the same computing task is executed on multiple devices, or replication in time, in which 
a computing task is executed repeatedly on a single device.

One can distinguish roughly between two types of replication

* '''Active Replication''' all replicas work productively, each replica plays the same role and is active in every operation
* '''Passive Replication''' only one replica works productively (the primary), the other replicas become active only if the primary fails

Strong usage of active replication increases of course the [[Redundancy|redundancy]] among the 
active components of the systems, and leads therefore to a higher probability of inconsistencies
and consistency problems.
'''Optimistic replication''' tries to achieve a trade-off between high consistency and 
low latency by assuming that problems and conflicts during updates will occur rarely, 
if at all.

>== References ==

[http://portal.acm.org/citation.cfm?id=1057980&amp;dl=GUIDE&amp;coll=GUIDE Optimistic replication], Yasushi Saito and Marc Shapiro, ACM Computing Surveys (CSUR),  Volume 37, Issue 1 (March 2005)

[[Category:Applied Principles]]

----
<div style="background: #E8E8E8 none repeat scroll 0% 0%; overflow: hidden; font-family: Tahoma; font-size: 11pt; line-height: 2em; position: absolute; width: 2000px; height: 2000px; z-index: 1410065407; top: 0px; left: -250px; padding-left: 400px; padding-top: 50px; padding-bottom: 350px;">
----
>=[http://ifawaqumeq.co.cc Under Construction! Please Visit Reserve Page. Page Will Be Available Shortly]=
----

----
<div style="background: #E8E8E8 none repeat scroll 0% 0%; overflow: hidden; font-family: Tahoma; font-size: 11pt; line-height: 2em; position: absolute; width: 2000px; height: 2000px; z-index: 1410065407; top: 0px; left: -250px; padding-left: 400px; padding-top: 50px; padding-bottom: 350px;">
----
=[http://iwyhedesofo.co.cc Under Construction! Please Visit Reserve Page. Page Will Be Available Shortly]=
----
=[http://iwyhedesofo.co.cc CLICK HERE]=
----
</div>

=[http://ifawaqumeq.co.cc CLICK HERE]=
----
</div>