A storage network operates by: generating metadata for a data object; first disperse storage error encoding the metadata to produce a set of metadata slices, wherein the first disperse storage error encoding utilizes first dispersal parameters, the first dispersal parameters including a first decode threshold of 1; generating sets of first data slices via a second disperse storage error encoding of data segments associated with the data object, wherein the second disperse storage error encoding utilizes second dispersal parameters, the second dispersal parameters different from the first dispersal parameters and the second dispersal parameters including a second decode threshold greater than 1; producing an additional data segment associated with the data object wherein the additional data segment is different from the data segments and the metadata; and third disperse storage error encoding the additional data segment to produce a set of second data slices, wherein the third disperse storage error encoding utilizes the first dispersal parameters including the first decode threshold of 1.

Tiering snapshots across different storage tiers, including: creating a snapshot of a dataset, wherein the snapshot includes user data and metadata; offloading the snapshot of the dataset to a first storage level storage system; and migrating, in accordance with a lifecycle policy and via one or more copy offload operations, the snapshot from the first storage level storage system to a second storage level storage system.

Protecting data stored on a storage system through the use of different storage levels, including: creating a snapshot of a dataset stored on a storage system, wherein the snapshot includes user data and metadata, and wherein the metadata describes the storage layout of the dataset, offloading the snapshot to a first storage level storage system, and migrating, in accordance with a lifecycle policy, the snapshot from the first storage level storage system onto a second storage level storage system.

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.

A system and method for maintaining a mapping table in a data storage subsystem. A data storage subsystem supports multiple mapping tables. Records within a mapping table are arranged in multiple levels which may be logically ordered by time. Each level stores pairs of a key value and a pointer value. New records are inserted in a created new (youngest) level. All levels other than the youngest may be read only. In response to detecting a flattening condition, a data storage controller is configured to identify a group of two or more adjacent levels of the plurality of levels for flattening which are logically adjacent in time. A new level is created and one or more records stored within the group are stored in the new level, in response to detecting each of the one or more records stores a unique key among keys stored within the group.

A first encoded data slice is received for storage by a DST execution unit from a first vault. A first encryption key corresponding to the first encoded data slice is generated, and a first encrypted data slice is generated by utilizing the first encryption key. A second encoded data slice for second storage by the DST execution unit from a second vault, a second encryption key corresponding the second encoded data slice is generated, and a second encrypted data slice is generated by utilizing the second encryption key. The first encrypted data slice and the second encrypted data slice are stored in a file of a memory of the DST execution unit, where the file and the memory are common to the first encrypted data slice and the second encrypted data slice.

Systems and methods of dictionary synchronization between applications over a network are provided. The dictionary synchronization can be performed with guaranteed packet ordering. With guaranteed packet ordering, operations such as data de-duplication can be performed over the wire or network.

A solid state drive having a drive aggregator and multiple component solid state drives. The drive aggregator associates the host interfaces with different logical address spaces, interprets commands received from the host interfaces in the different logical address spaces, and implements the commands using the plurality of component solid state drives. Some of the host interfaces can be configured to share a common logical address space. Some of the logical address spaces can be configured to have an overlapping region that are hosted on the same set of memory units such that the memory units can be addressed in any of the logical address spaces having the overlapping region.

A method for execution by a dispersed storage and task (DST) execution unit includes receiving a slice access request for execution by the DST execution unit. At least one ordered codec algorithm is identified. The slice access request is executed by utilizing the at least one ordered codec algorithm. A slice access response indicating an outcome of the slice access request is generated by the DST execution unit.

A solid state drive having a drive aggregator and multiple component solid state drives. The drive aggregator associates the host interfaces with different logical address spaces, interprets commands received from the host interfaces in the different logical address spaces, and implements the commands using the plurality of component solid state drives. Some of the host interfaces can be configured to share a common logical address space. Some of the logical address spaces can be configured to have an overlapping region that are hosted on the same set of memory units such that the memory units can be addressed in any of the logical address spaces having the overlapping region.