Abstract: A controller of a Solid State Device (SSD) defines a mapping from memory devices, such as flash packages, that make up the SSD to one or more storage virtual containers. The storage virtual containers are exposed to an operating system by the controller through an interface. The operating system may then make operation requests to the one or more storage virtual containers, and the controller may use the mapping to fulfill the operation requests from the corresponding flash packages. The storage virtual containers are mapped to the flash packages to take advantage of the parallelism of the flash packages in the SSD so that the controller may fulfill operation requests received from the operating system in parallel.

Abstract: A system and method accelerates update of a metadata search database using PCPI differencing. After first populating the search database, a search agent generates a PCPI and utilizes a PCPI differencing technique to quickly identify changes between inode files of first and second PCPIs. The differences are noted as modified metadata and are written to a log file, which is later read by the search agent to update the search database.

Abstract: A hybrid storage device uses a write cache such as a hard disk drive, for example, to cache data to a solid state drive (SSD). Data is logged sequentially to the write cache and later migrated to the SSD. The SSD is a primary storage that stores data permanently. The write cache is a persistent durable cache that may store data of disk write operations temporarily in a log structured fashion. A migration policy may be used to determine how long to cache the data in the write cache before migrating the data to the SDD. The migration policy may be implemented using one or more migration triggers that cause the contents of the write cache to be flushed to the SSD. Migration triggers may include a timeout trigger, a read threshold trigger, and a migration size trigger, for example.

Abstract: A job scheduler may schedule concurrent distributed jobs in a computer cluster by assigning tasks from the running jobs to compute nodes while balancing fairness with efficiency. Determining which tasks to assign to the compute nodes may be performed using a network flow graph. The weights on at least some of the edges of the graph encode data locality, and the capacities provide constraints that ensure fairness. A min-cost flow technique may be used to perform an assignment of the tasks represented by the network flow graph. Thus, online task scheduling with locality may be mapped onto a network flow graph, which in turn may be used to determine a scheduling assignment using min-cost flow techniques. The costs may encode data locality, fairness, and starvation-freedom.

Abstract: Multiple versions of data on different sets of machines allow a system to degrade gracefully even when experiencing excessive failures. When excessive failures cause the latest versions to be unavailable, the system becomes degraded, but still offers an old version if available. A most recent coherent set of the available older versions is found and provided. The degree of degradation increases gradually as the system experiences more and more failures. Graceful degradation is desirably complementary to fault tolerance.

Abstract: A controller of a Solid State Device (SSD) defines a mapping from memory devices, such as flash packages, that make up the SSD to one or more storage virtual containers. The storage virtual containers are exposed to an operating system by the controller through an interface. The operating system may then make operation requests to the one or more storage virtual containers, and the controller may use the mapping to fulfill the operation requests from the corresponding flash packages. The storage virtual containers are mapped to the flash packages to take advantage of the parallelism of the flash packages in the SSD so that the controller may fulfill operation requests received from the operating system in parallel.

Abstract: A cyclic commit protocol is used to store relationships between transactions and is used by the technology to determine whether a transaction is committed or not. The protocol allows creation of a cycle of transactions which can be used to recover the state of a storage device after a host failure by identifying the last committed version of intention records as committed or uncommitted based on the data stored in the physical pages.

Abstract: A system and method accelerates update of a metadata search database using PCPI differencing. After first populating the search database, a search agent generates a PCPI and utilizes a PCPI differencing technique to quickly identify changes between inode files of first and second PCPIs. The differences are noted as modified metadata and are written to a log file, which is later read by the search agent to update the search database.

Abstract: Multiple versions of data on different sets of machines allow a system to degrade gracefully even when experiencing excessive failures. When excessive failures cause the latest versions to be unavailable, the system becomes degraded, but still offers an old version if available. A most recent coherent set of the available older versions is found and provided. The degree of degradation increases gradually as the system experiences more and more failures. Graceful degradation is desirably complementary to fault tolerance.