Abstract: The method, apparatus, and system disclosed herein relate to a faster and more predictable way to achieve synchronous phase from non-synchronous phase for synchronous data replication between a source volume and a destination volume. Consistency data and replication data are sent in parallel during a pre-synchronous phase to reestablish a synchronous phase of operation. Sequence identifiers and consistency sequence identifiers are used to determine whether to write consistency data to the destination volume, or to leave consistency data unwritten for blocks already updated with replication data during the process of reestablishing synchronization.

Abstract: Systems and methods are described for fully replacing an online first RAID group of data storage devices with a second RAID group of data storage devices, whereby the data is read in parallel from multiple devices in the first group and written in parallel to multiple devices in the second group. Sub-chunks of data chunks not currently storing any data may be bypassed from copying, as well as sub-chunks still storing data that is no longer in-use by a client. The data may be copied as-is rather than from and to the same logical block address on each respective group. A similar process may be applied for shrinking the number of storage devices allocating to a storage pool.

Abstract: Example storage systems, storage controllers, and methods provide data redundancy reconfiguration using logical subunits. Storage devices are configured in a storage group with a first data redundancy configuration. A second data redundancy configuration is selected and the space available in the storage group is determined. For each logical data unit, logical data subunits are selected, written to the space available in the second data redundancy configuration, and deleted from the logical data unit. Storage operations using the storage group may be maintained during the migration process.

Abstract: A disclosed method for managing a RAID (redundant array of independent devices) file system memory comprises coalescing small read and write chunks into reasonably sized coalesced chunks up to 1 MB without any small size I/Os. The method also includes creating a new mapping layer configured to map the small size chunks in the coalesced chunks. The method additionally comprises flushing the coalesced chunks by allocating large chunks based on a chunk size coalescence or on a check point hit in terms of a SPA Sync. The method may also include applying a dynamic parity algorithm on the coalesced chunks to generate parities and data fragmented columns in reasonably big sized chunks. The method may yet include creating an appropriate coalesced chunk header to maintain the new mapping layer. The method may still comprise generating a chunked block pointer and a regular block pointer configured to co-exist in dual process threads.

Abstract: A process for reconstructing data stored on a failed storage drive in a RAID storage system involves performing a resilvering procedure on a first portion of the data for reconstruction and performing a recompaction procedure on the remaining portion of the data for reconstruction. Because the resilvering procedure rebuilds its data only on the replacement storage drive, but the recompaction procedure rebuilds its data on one or more, likely multiple, non-failed storage drives, the additional bandwidth provided by the non-failed drives is utilized to increase the speed of the overall data reconstruction. Determining how much of the data storage chunk processing to distribute to the resilvering and to the recompaction procedures may be based on the respective write workloads of the replacement and non-failed drives, as well as on the percentage of free storage space available from each of the chunks.

Abstract: A method, system and computer program product for managing an amount of storage written from a transaction group comprises creating a plurality of transaction classes within each of a plurality of write transaction classes and discovering an initial underlying drive capability assignable to the transaction classes when a storage pool is allocated (SPA). Each transaction class capability weight is adjusted via computing an instruction and operations per second, a data rate per second and a time slice at every storage pool allocator sync time. An unspent time slice from an adjusted transaction class is lent to a plurality of remaining transaction classes yet to be adjusted via a staged processing distribution during sync of the SPA. The disclosed method further includes assigning system resources and underlying drive capability to each transaction class per its capability weight based on a ratio of weights for each transaction class of operations.

Abstract: A method, system and computer program product for managing a file system includes a plurality of allocation areas of loaded allocation trees to serve a request per file system drive for a transaction group. The system also includes a module configured to move a loaded allocation tree to an unloading tree in the event the loaded allocation tree will not satisfy the request. The system additionally includes a module configured to select and place in a loading tree queue a most eligible unloaded tree based on a weight of each unloaded tree. The system further includes a module to asynchronously process the loading tree queue and an unloading tree queue threads parallel to a storage pool allocator sync process. Allocation areas are attached in a circular ring of loaded allocation trees. Space map trees are converted into fixed size areas for constant latency loading logs and creating index trees.