Abstract: According to an embodiment, a method to quantify domain-centric risk is disclosed. The method comprises: receiving at least one first input associated with a loss event frequency from at least one first external source in a Risk assessment engine; receiving at least one second input associated with a Loss Magnitude from at least one second external source in the Risk assessment engine; receiving at least one third input associated with a plurality of domain-centric entities from at least one third external source in the Risk assessment engine; analyzing the loss event frequency, the loss magnitude, and the at least one third input to quantify the risk associated with a target domain-centric entity; and generating a risk assessment report for the target domain-centric entity based on the analysis of the loss event frequency, the loss magnitude, and the at least one third input.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for executing concurrent writes to a data store. One of the systems includes a data store comprising a plurality of storage segments, wherein each storage segment comprises a plurality of blocks; and an allocator system comprising: a plurality of threads, and a plurality of bitmaps each corresponding to a respective storage segment of the data store, wherein the allocator system is configured to perform operations comprising: assigning a respective bitmap to each thread of the plurality of threads; and executing, by each thread of the plurality of threads, one or more write requests to one or more blocks of the storage segment corresponding to the thread using the bitmap assigned to the thread, wherein executing a write request by a thread includes updating the bitmap assigned to the thread.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for executing concurrent writes to a data store. One of the systems includes a data store comprising a plurality of storage segments, wherein each storage segment comprises a plurality of blocks; and an allocator system comprising: a plurality of threads, and a plurality of bitmaps each corresponding to a respective storage segment of the data store, wherein the allocator system is configured to perform operations comprising: assigning a respective bitmap to each thread of the plurality of threads; and executing, by each thread of the plurality of threads, one or more write requests to one or more blocks of the storage segment corresponding to the thread using the bitmap assigned to the thread, wherein executing a write request by a thread includes updating the bitmap assigned to the thread.

Abstract: Destaging data from a first tier data store to a second tier data store can be performed periodically and concurrently while processing user I/O operations. Each round of destaging can be delayed by certain amount (sleep time). A throttling factor can be used to compute the sleep time as a fraction of a base sleep time. The throttling factor can vary based on the usage level of first tier data store, and can be used to determine the destage frequency.

Abstract: Destaging data from a first tier data store to a second tier data store can be performed periodically and concurrently while processing user I/O operations. Each round of destaging can be delayed by certain amount (sleep time). A throttling factor can be used to compute the sleep time as a fraction of a base sleep time. The throttling factor can vary based on the usage level of first tier data store, and can be used to determine the destage frequency.

Abstract: A given host machine in a virtualization system having a virtual distributed storage system may receive an iSCSI protocol packet from a computer system separate from the given host machine. Processing the iSCSI protocol may include accessing distributed storage device (iSCSI target) comprising storage connected to the two or more host machines in the virtualization system. The given host machine may generate an outbound iSCSI protocol packet comprising return data received from the target and send the outbound iSCSI protocol packet to the computer system.

Abstract: A given host machine in a virtualization system having a virtual distributed storage system may receive an iSCSI protocol packet from a computer system separate from the given host machine. Processing the iSCSI protocol may include accessing distributed storage device (iSCSI target) comprising storage connected to the two or more host machines in the virtualization system. The given host machine may generate an outbound iSCSI protocol packet comprising return data received from the target and send the outbound iSCSI protocol packet to the computer system.