16. A computer system comprising: a central processing unit (CPU); a memory coupled to the CPU; and a computer-readable storage device coupled to the CPU, the storage device containing instructions that are executed by the CPU via the memory to implement a method of managing replicated data, the method comprising the steps of: the computer system receiving first metadata specifying inter-data correlation(s), which are correlation(s) between sets of replicated data in a first set of replicas; the computer system receiving second metadata specifying inter-replica correlation(s), which are correlation(s) between replicas included in a second set of replicas; the computer system receiving third metadata specifying data-replica correlation(s), which are correlation(s) between set(s) of replicated data and respective replica(s) included in a third set of replicas, the first, second and third sets of replicas being included in a plurality of replicas generated for a replicated data management system; the computer system determining a current usage of resources in the replicated data management system and a threshold usage of the resources; the computer system generating a unified replication metadata model specifying the inter-data correlation(s) based on the first metadata, the inter-replica correlation(s) based on the second metadata, and the data-replica correlation(s) based on the third metadata; based on the inter-replica correlation(s) specified by the unified replication metadata model, the computer system selecting a proper subset of replicas included in the plurality of replicas; based on the inter-replica and inter-data correlation(s) specified by the unified replication metadata model, the computer system indexing the selected proper subset of replicas to generate a unified content index, wherein the step of indexing the selected proper subset includes: if the current usage is less than the threshold usage, then the computer system determining an expected additional resource usage due to performing an indexing task online, and based on the expected additional resource usage, the computer system determining a resource affinity score for performing the indexing task online; and if the current usage is greater than or equal to the threshold usage, then the computer system determining an expected resource usage due to performing the indexing task offline and based on the expected resource usage, the computer system determining a resource affinity score for performing the indexing task offline; the computer system receiving a query to locate a data item in at least one replica included in the plurality of replicas; and based on the unified content index, the unified replication metadata model, and the received query, the computer system determining candidate replica(s) and corresponding confidence score(s), the confidence score(s) indicating respective likelihood(s) that the candidate replica(s) include the data item, and the candidate replica(s) included in the plurality of replicas.
16. A computer system comprising: a central processing unit (CPU); a memory coupled to the CPU; and a computer-readable storage device coupled to the CPU, the storage device containing instructions that are executed by the CPU via the memory to implement a method of managing replicated data, the method comprising the steps of: the computer system receiving first metadata specifying inter-data correlation(s), which are correlation(s) between sets of replicated data in a first set of replicas; the computer system receiving second metadata specifying inter-replica correlation(s), which are correlation(s) between replicas included in a second set of replicas; the computer system receiving third metadata specifying data-replica correlation(s), which are correlation(s) between set(s) of replicated data and respective replica(s) included in a third set of replicas, the first, second and third sets of replicas being included in a plurality of replicas generated for a replicated data management system; the computer system determining a current usage of resources in the replicated data management system and a threshold usage of the resources; the computer system generating a unified replication metadata model specifying the inter-data correlation(s) based on the first metadata, the inter-replica correlation(s) based on the second metadata, and the data-replica correlation(s) based on the third metadata; based on the inter-replica correlation(s) specified by the unified replication metadata model, the computer system selecting a proper subset of replicas included in the plurality of replicas; based on the inter-replica and inter-data correlation(s) specified by the unified replication metadata model, the computer system indexing the selected proper subset of replicas to generate a unified content index, wherein the step of indexing the selected proper subset includes: if the current usage is less than the threshold usage, then the computer system determining an expected additional resource usage due to performing an indexing task online, and based on the expected additional resource usage, the computer system determining a resource affinity score for performing the indexing task online; and if the current usage is greater than or equal to the threshold usage, then the computer system determining an expected resource usage due to performing the indexing task offline and based on the expected resource usage, the computer system determining a resource affinity score for performing the indexing task offline; the computer system receiving a query to locate a data item in at least one replica included in the plurality of replicas; and based on the unified content index, the unified replication metadata model, and the received query, the computer system determining candidate replica(s) and corresponding confidence score(s), the confidence score(s) indicating respective likelihood(s) that the candidate replica(s) include the data item, and the candidate replica(s) included in the plurality of replicas. 20. The computer system of claim 16 , wherein the step of indexing the selected proper subset of replicas includes the steps of: the computer system determining index updates by determining keyword-to-replica mappings; and the computer system generating the unified content index based on the index updates.