Abstract: Techniques are provided for repairing a primary slice file, affected by a storage device error, by using one or more dead replica slice files. The primary slice file is used by a node of a distributed storage architecture as an indirection layer between storage containers (e.g., a volume or LUN) and physical storage where data is physically stored. To improve resiliency of the distributed storage architecture, changes to the primary slice file are replicated to replica slice files hosted by other nodes. If a replica slice file falls out of sync with the primary slice file, then the replica slice file is considered dead (out of sync) and could potentially comprise stale data. If a storage device error affects blocks storing data of the primary slice file, then the techniques provided herein can repair the primary slice file using non-stale data from one or more dead replica slice files.

Abstract: It is determined that a first data unit is to be written to a storage device and that the first data unit is associated with a first attribute. In response to determining that the first data unit is associated with the first attribute, a first identifier is selected from a first identifier space and the first identifier is associated with the first data unit. It is determined that a second data unit is to be written to the storage device and that the second data unit is associated with the second attribute. In response to determining that the second data unit is associated with the second attribute, a second identifier is selected from a second identifier space and the second identifier is associated with the second data unit.

Abstract: It is determined that a first data unit is to be written to a storage device and that the first data unit is associated with a first attribute. In response to determining that the first data unit is associated with the first attribute, a first identifier is selected from a first identifier space and the first identifier is associated with the first data unit. It is determined that a second data unit is to be written to the storage device and that the second data unit is associated with the second attribute. In response to determining that the second data unit is associated with the second attribute, a second identifier is selected from a second identifier space and the second identifier is associated with the second data unit.

Abstract: A method performed in a network storage system, the method including receiving a plurality of data blocks at a secondary storage subsystem from a primary storage subsystem, generating a first log that includes a first plurality of entries, one entry for each of the data blocks, in which each entry of the first plurality of entries includes a name for a respective data block and a fingerprint of the respective data block, receiving metadata at the secondary storage subsystem from the primary storage subsystem, the metadata describing relationships between the plurality of blocks and a plurality of files, generating a second log that includes a second plurality of entries, and merging the first log with the second log to generate a change log.

Abstract: Techniques for a method of estimating deduplication potential are disclosed herein. The method includes steps of selecting randomly a plurality of data blocks from a data set as a sample of the data set, collecting fingerprints of the plurality of data blocks of the sample, identifying duplicates of fingerprints of the sample from the fingerprints of the plurality of data blocks, estimating a total number of unique fingerprints of the data set depending on a total number of the duplicates of fingerprints of the sample based on a probability of fingerprints from the data set colliding in the sample, and determining a total number of duplicates of fingerprints of the data set depending on the total number of the unique fingerprints of the data set.

Abstract: A method performed in a network storage system, the method including receiving a plurality of data blocks at a secondary storage subsystem from a primary storage subsystem, generating a first log that includes a first plurality of entries, one entry for each of the data blocks, in which each entry of the first plurality of entries includes a name for a respective data block and a fingerprint of the respective data block, receiving metadata at the secondary storage subsystem from the primary storage subsystem, the metadata describing relationships between the plurality of blocks and a plurality of files, generating a second log that includes a second plurality of entries, and merging the first log with the second log to generate a change log.

Abstract: A method performed in a network storage system, the method including receiving a plurality of data blocks at a secondary storage subsystem from a primary storage subsystem, generating a first log that includes a first plurality of entries, one entry for each of the data blocks, in which each entry of the first plurality of entries includes a name for a respective data block and a fingerprint of the respective data block, receiving metadata at the secondary storage subsystem from the primary storage subsystem, the metadata describing relationships between the plurality of blocks and a plurality of files, generating a second log that includes a second plurality of entries, and merging the first log with the second log to generate a change log.