Abstract: A technique provides efficient data failover by creation and deployment of a protection policy that ensures maintenance of frequent common snapshots between sites of a multi-site data replication environment. A global constraint optimizer executes on a node of a cluster to create the protection policy for deployment among other nodes of clusters at the sites. Constraints such as protection rules (PRs) specifying, e.g., an amount of tolerable data loss are applied to a category of data designated for failover from a primary site over a network to a plurality of (secondary and tertiary) sites typically located at geographically separated distances. The optimizer processes the PRs to compute parameters such as frequency of snapshot generation and replication among the sites, as well as retention of the latest common snapshot maintained at each site to create a recovery point and configuration of the protection policy that reduces network traffic for efficient use of the network among the sites.

Abstract: A technique provides efficient data failover by creation and deployment of a protection policy that ensures maintenance of frequent common snapshots between sites of a multi-site data replication environment. A global constraint optimizer executes on a node of a cluster to create the protection policy for deployment among other nodes of clusters at the sites. Constraints such as protection rules (PRs) specifying, e.g., an amount of tolerable data loss are applied to a category of data designated for failover from a primary site over a network to a plurality of (secondary and tertiary) sites typically located at geographically separated distances. The optimizer processes the PRs to compute parameters such as frequency of snapshot generation and replication among the sites, as well as retention of the latest common snapshot maintained at each site to create a recovery point and configuration of the protection policy that reduces network traffic for efficient use of the network among the sites.

Abstract: A technique creates a compact state of snapshot metadata and associated selected snapshots that are frequently used and maintained in memory of a node of a cluster to facilitate processing of workflow operations associated with a logical entity in a disaster recovery (DR) environment. The compact state represents a minimal subset of snapshot metadata that is frequently used to perform operations in accordance with the DR workflow operations. In addition, metadata associated with the progress of the DR workflow operations processed by the node is periodically consolidated within the compact state. Illustratively, the selected frequently used snapshots of the logical entity include (i) a recently created snapshot; (ii) one or more reference snapshots; (iii) a snapshot scheduled for replication; and (iv) any snapshot that is queued for a current or future-scheduled operation.

Abstract: A technique provides efficient data failover by creation and deployment of a protection policy that ensures maintenance of frequent common snapshots between sites of a multi-site data replication environment. A global constraint optimizer executes on a node of a cluster to create the protection policy for deployment among other nodes of clusters at the sites. Constraints such as protection rules (PRs) specifying, e.g., an amount of tolerable data loss are applied to a category of data designated for failover from a primary site over a network to a plurality of (secondary and tertiary) sites typically located at geographically separated distances. The optimizer processes the PRs to compute parameters such as frequency of snapshot generation and replication among the sites, as well as retention of the latest common snapshot maintained at each site to create a recovery point and configuration of the protection policy that reduces network traffic for efficient use of the network among the sites.

Abstract: Methods, computer program products, computer systems, and the like are disclosed that provide for the tracking of access patterns of inodes, and the issuing of inode read-ahead instructions, in order to pre-fetch inodes. Such a method can include, for example, identifying a unit of metadata in a file system, identifying a file system structure in the file system, determining whether a file structure of the file system structure is non-sequential, and, in response to a determination that the file structure is non-sequential, retrieving a list of units of metadata. In such embodiments, the file system structure is associated with the unit of metadata, and the determining includes accessing the file system structure. Further, in certain embodiments, the units of metadata identified in the list of units of metadata are stored in a storage device of the computer system.

Abstract: Disclosed herein are methods, systems, and processes to track access patterns of inodes, and to issue read-ahead instructions to pre-fetch inodes into memory. A location of a unit of metadata in a metadata storage area is determined. Another location in the metadata storage area that corresponds to a current metadata read operation is determined. Whether a metadata read-ahead operation can be performed is determined using the location of the unit of metadata and the another location. In response to a determination that the metadata read-ahead operation can be performed, the metadata-ahead operation is issued.

Abstract: The disclosed computer-implemented method for delayed allocation in cluster storage may include (i) delegating, to a node attached to a storage cluster including one or more storage devices that include a group of allocation units, a subset of allocation units on the storage cluster to be held as a delayed allocation pool, (ii) receiving, from the node, a request to allocate allocation units on the storage cluster, (iii) deducting the number of allocation units from available allocation units in the delayed allocation pool, (iv) satisfying the allocation request by allocating allocation units not in the delayed allocation pool before allocating allocation units included in the delayed allocation pool, and (v) recalculating, based on the number of allocation units in the delayed allocation pool used to satisfy the allocation request, the number of available allocation units in the delayed allocation pool. Various other methods, systems, and computer-readable media are also disclosed.

Abstract: Disclosed herein are methods, systems, and processes track access patterns of inodes, and to issue read-ahead instructions to pre-fetch inodes into memory. An inode is accessed and a directory of the inode is determined. Also determined is whether an entry for the directory exists in a global inode list. If the entry exists in the global inode list, whether a file structure of the directory is sequential or non-sequential is determined. If the entry does not exist in the global inode list, a new entry for the directory is added in the global inode list.

Abstract: The disclosed computer-implemented method for efficiently moving data within a filesystem may include (1) partitioning, on a storage device, physical address space of a filesystem into a plurality of logical partitions, (2) allocating, on the storage device, at least one container of data block identifiers representing data blocks for each of the logical partitions, (3) maintaining, on the storage device, a partition map of values identifying the container of data block identifiers, the logical partitions, and at least one offset associated with each of the logical partitions, (4) sending, on the storage device, the data blocks from a source logical partition within the logical partitions to a target logical partition within the logical partitions, and (5) updating, on the storage device, the partition map based on the data blocks sent from the source logical partition to the target logical partition. Various other methods, systems, and computer-readable media are also disclosed.

Abstract: Disclosed herein are methods, systems, and processes to track access patterns of inodes, and to issue read-ahead instructions to pre-fetch inodes into memory. A location of a unit of metadata in a metadata storage area is determined. Another location in the metadata storage area that corresponds to a current metadata read operation is determined. Whether a metadata read-ahead operation can be performed is determined using the location of the unit of metadata and the another location. In response to a determination that the metadata read-ahead operation can be performed, the metadata-ahead operation is issued.

Abstract: Disclosed herein are methods, systems, and processes track access patterns of inodes, and to issue read-ahead instructions to pre-fetch inodes into memory. An inode is accessed and a directory of the inode is determined. Also determined is whether an entry for the directory exists in a global inode list. If the entry exists in the global inode list, whether a file structure of the directory is sequential or non-sequential is determined. If the entry does not exist in the global inode list, a new entry for the directory is added in the global inode list.

Abstract: Various systems and methods use advisory metadata to track the status of file system objects. For example, one method can involve accessing a first item of advisory metadata, which is associated with a namespace-visible parent directory and identifies a first transaction and a first time, and accessing a second item of advisory metadata, which is also associated with the namespace-visible parent directory and identifies a second transaction and a second time. The namespace visible parent directory includes multiple namespace-hidden directories. The method can then select a time value of the advisory metadata for the namespace-visible parent directory, based upon the first item and the second item. The method can be performed by a computing device implementing a file system.

Abstract: Systems and methods for inode use are presented. In one embodiment; an inode reuse method includes: receiving an indication of an operation that involves access to file related information; assigning an inode to the access; identifying one of a plurality of inode reuse scenarios for the inode; and making the inode available for reuse in accordance with the one of the plurality of inode reuse scenarios. In one embodiment, the one of the plurality of inode reuse scenarios is a relatively expedited reuse scenario. In one exemplary implementation, the relatively expedited inode reuse scenario is utilized if the inode is not required for further processing associated with the operation. The inode can be reused for another immediately subsequent operation.

Abstract: Systems and methods for inode use are presented. In one embodiment; an inode reuse method includes: receiving an indication of an operation that involves access to file related information; assigning an inode to the access; identifying one of a plurality of inode reuse scenarios for the inode; and making the inode available for reuse in accordance with the one of the plurality of inode reuse scenarios. In one embodiment, the one of the plurality of inode reuse scenarios is a relatively expedited reuse scenario. In one exemplary implementation, the relatively expedited inode reuse scenario is utilized if the inode is not required for further processing associated with the operation. The inode can be reused for another immediately subsequent operation.