Optimal replication
Optimal replication
Background
Data replication is used to minimise the possibility of access failures to urgently required data (high access availability), but also to reduce access times to this data. The working group recently created a CORBA-based prototype for consistent data replication, which is used to manage replicated WWW documents. This prototype includes a component that allows any so-called static Coterie-based replication procedure to be specified and used to manage documents on the WWW. The specification of a desired special replication strategy is carried out by specifying an acyclic graph (in text form according to a formal language). The extension of this component to capture and process a further class of Coterie-based replication strategies is also available: the extension relates to so-called dynamic replication strategies. These are generally characterised by higher access costs on the one hand and higher access availability of the replicated WWW document on the other.
Job description
The aim of this thesis is to develop an optimal dynamic replication strategy. For this purpose, it must be determined which of the static replication strategies known to date has the maximum quality in terms of read and write costs and read and write availability for 1) which number of replicas, 2) which read/write rate and 3) which underlying computer availability. The results of these analyses lead to a kind of table that contains the best static replication strategies for the individual cases. Based on this table, a dynamic replication strategy is to be implemented that uses the most favourable static replication strategy for the individual situations. Based on the implementation, a comparison is to be made experimentally with previous dynamic replication strategies whose dynamics are based solely on the variation of a single static replication strategy.