Abstract: Multiple nodes of a cluster have associated non-shared, local caches, used to cache shared storage content. Each local cache is accessible only to the node with which it is associated, whereas the cluster-level shared storage is accessible by any of the nodes. Attempts to access the shared storage by the nodes of the cluster are monitored. Information is tracked concerning the current statuses of the local caches of the nodes of the cluster. Current tracked local cache status information is maintained, and stored such that it is accessible by the multiple nodes of the cluster. The current tracked local cache status information is used in conjunction with the caching functionality to determine whether specific nodes of the cluster are to access their local caches or the shared storage to obtain data corresponding to specific regions of the shared storage.

Abstract: A computer-implemented method for file-level replication may include 1) identifying a selection of at least one source file to replicate from a primary volume to a secondary volume, 2) identifying extent information that indicates a volume location of the source file within the primary volume, 3) identifying a volume offset within the primary volume of a write operation performed on the source file within the primary volume, 4) converting the volume offset to a file offset within the source file using the extent information, and 5) replicating the write operation and the file offset to the secondary volume. Various other methods and systems are also disclosed.

Abstract: A method for virtual disk usage transparency may include 1) identifying a secondary volume at a secondary site configured for synchronization with a primary volume at a primary site, 2) identifying a set of blocks present within the primary volume but not present within the secondary volume, 3) identifying a virtual disk file within the primary volume, the virtual disk file including at least one block within the set of blocks, 4) determining that the block represents an unused block within a guest file system configured to use the virtual disk file, 5) selecting a subset of the set of blocks to transmit from the primary site to the secondary site, where selecting the subset includes excluding the block from the subset, and 6) transmitting the subset of the set of blocks from the primary site to the secondary site. Various other methods, systems, and computer-readable media are also disclosed.

Abstract: Various systems and methods for performing write-back caching in a cluster. For example, one method can involve a first node detecting that no failover nodes are available. A determination is made whether the first node should use write-back caching or not. If the first node is to continue using write-back caching, a first local cache identifier and a global cache identifier are both updated.