Abstract: Compounding file system metadata operations via buffering is disclosed. In various embodiments, an indication to send locally-stored file system operations to a remote file system metadata server is received. A dependency graph or other data structure reflecting dependencies between the locally-stored file system operations to identify a linear chain of dependent file system operations. Operations comprising the linear chain are combined into a compound file system operation. The compound file system operation is sent to the remote file system metadata server.

Abstract: Cancelling file system operations at a file system client of a distributed file system is disclosed. In various embodiments, an indication is received to send locally-stored file system operations to a remote file system metadata server. A dependency graph or other data structure reflecting dependencies between the locally-stored file system operations is used to identify a set of locally-stored file system operations the members of which are fully dominated by a create-delete pair of operations comprising the set. The locally-stored file system operations comprising the set are cancelled, without being sent to the remote file system metadata server.

Abstract: Techniques to eliminate redundant file system operations are disclosed. In various embodiments, an indication is received to send locally-stored file system operations to a remote file system metadata server. A set of related locally-stored file system operations is determined. Operations in the set are determined to satisfy a merger criteria and are merged into a single merged file system operation. The merged file system operation is sent to the remote file system metadata server.

Abstract: An improved blockchain implementation that uses proof-of-transfer to overcome the technical deficiencies of proof of work and proof-of-stake implementations is described herein. For example, the proof-of-transfer process may include elements of a single-leader election sortition, but modified to cause base chain cryptocurrency committed for the purposes of the sortition to be transferred to a burn address or at least one reward address.

Abstract: An improved blockchain implementation that uses proof-of-transfer to overcome the technical deficiencies of proof of work and proof-of-stake implementations is described herein. For example, the proof-of-transfer process may include elements of a single-leader election sortition, but modified to cause base chain cryptocurrency committed for the purposes of the sortition to be transferred to a burn address or at least one reward address.

Abstract: Several methods and a system of a replicated service for write ahead logs are disclosed. In one embodiment, a method includes persisting a state of a distributed system through a write ahead log (WAL) interface. The method also includes maintaining a set of replicas of a WAL through a consensus protocol. In addition, the method includes providing a set of mechanisms for at least one of detection and a recovery from a hardware failure. The method further includes recovering a persistent state of a set of applications. In addition, the method includes maintaining the persistent state across a set of nodes through the hardware failover. In one embodiment, the system may include a WAL interface to persist a state of a distributed system. The system may also include a WAL replication servlet to maintain and/or recover a set of replicas of a WAL.

Abstract: A method in data storage involves receiving at a metadata server from a client device a BEGIN_WRITE request identifying data to be written by hashes, consulting, by the metadata server a deduplication table to determine historical nature of the data determined to be written, determining that the data was never previously written, was previously written by another client, or was previously written but failed a verification, sending to the client device write locations with tokens for the data, starting an authentication timer, and authorizing the client device to write directly to the data server using the authentication tokens and the authenticated write locations, determining that the data was previously written by the same client, or that the data was previously written and passed the verification test, notifying the client of this circumstance, and receiving from the client device an END_WRITE request.

Abstract: A method in data storage involves receiving at a metadata server from a client device a BEGIN_WRITE request identifying data to be written by hashes, consulting, by the metadata server a deduplication table to determine historical nature of the data determined to be written, determining that the data was never previously written, was previously written by another client, or was previously written but failed a verification, sending to the client device write locations with tokens for the data, starting an authentication timer, and authorizing the client device to write directly to the data server using the authentication tokens and the authenticated write locations, determining that the data was previously written by the same client, or that the data was previously written and passed the verification test, notifying the client of this circumstance, and receiving from the client device an END_WRITE request.

Abstract: A method comprises determining a flexible limit on an amount of resource usage by a driver domain on behalf of a given virtual machine (VM). The method further comprises controlling the resource usage by the driver domain on behalf of the given VM so as not to exceed the flexible limit except under a permitted condition. In certain embodiments the resource usage by the driver domain on behalf of the given VM is controlled so as not to exceed the flexible limit except when a slack share of resource usage is available to the driver domain. Such a slack share of resource usage is a share of resource usage allocated to the driver domain that will not otherwise be used on behalf of another VM.

Abstract: Several methods and a system of a replicated service for write ahead logs are disclosed. In one embodiment, a method includes persisting a state of a distributed system through a write ahead log (WAL) interface. The method also includes maintaining a set of replicas of a WAL through a consensus protocol. In addition, the method includes providing a set of mechanisms for at least one of detection and a recovery from a hardware failure. The method further includes recovering a persistent state of a set of applications. In addition, the method includes maintaining the persistent state across a set of nodes through the hardware failover. In one embodiment, the system may include a WAL interface to persist a state of a distributed system. The system may also include a WAL replication servlet to maintain and/or recover a set of replicas of a WAL.

Abstract: Several methods and a system of a replicated service for write ahead logs are disclosed. In one embodiment, a method includes persisting a state of a distributed system through a write ahead log (WAL) interface. The method also includes maintaining a set of replicas of a WAL through a consensus protocol. In addition, the method includes providing a set of mechanisms for at least one of detection and a recovery from a hardware failure. The method further includes recovering a persistent state of a set of applications. In addition, the method includes maintaining the persistent state across a set of nodes through the hardware failover. In one embodiment, the system may include a WAL interface to persist a state of a distributed system. The system may also include a WAL replication servlet to maintain and/or recover a set of replicas of a WAL.

Abstract: A method comprises scheduling, by a weighted proportional-share virtual time processor scheduler, processor access to a first consumer during a time period in which a second consumer is blocked from processor access. When the second consumer becomes unblocked from processor access, the weighted proportional-share virtual time processor scheduler determines whether the length of the time period over which the second consumer was blocked from processor access exceeds a predefined time threshold. When determined that the length of the time period over which the second consumer was blocked from processor access does not exceed the predefined time threshold, then scheduler does not update the virtual time of the second consumer before scheduling processor access for the second consumer.

Abstract: A method comprises observing communication through a virtualized interface between at least one virtual machine (VM) and a driver domain. Based on the observed communication through the virtualized interface, a weighted amount of communication between the VM and the driver domain is determined for each of the VM(s), wherein the weighted amount is based at least in part on at least one characteristic of the observed communication, such as directional flow and/or size of packets in the communication. Another method comprises evaluating CPU utilization of a target network driver domain in processing communications having different characteristics, and deriving corresponding weighting for the different communication characteristics. The derived weighting for the different communication characteristics are employed within a communication monitor that observes communication between virtual machines and the target network driver domain.

Abstract: A method comprises determining an amount of central processing unit (CPU) usage by a driver domain on behalf of a given virtual machine (VM) over a measurement period. The method further comprises determining a share of CPU to schedule for the given VM for a plurality of future scheduling intervals based at least in part on the determined amount of CPU usage by the driver domain on behalf of the given VM over the measurement period. The method further comprises scheduling the determined share of CPU access to the given VM for the plurality of future scheduling intervals.

Abstract: A method comprises determining an amount to which resource usage by a driver domain on behalf of a given virtual machine (VM) is to be limited. The method further comprises controlling the resource usage by the driver domain on behalf of the given VM so as not to exceed the determined amount. A system comprises a VM, a driver domain, and a shared resource that is usable by the VM and by the driver domain. The system further comprises a controller for limiting usage of the shared resource by the driver domain on behalf of the VM to prevent the usage of the shared resource by the driver domain on behalf of the VM from exceeding a determined amount.

Abstract: Several methods and a system of a replicated service for write ahead logs are disclosed. In one embodiment, a method includes persisting a state of a distributed system through a write ahead log (WAL) interface. The method also includes maintaining a set of replicas of a WAL through a consensus protocol. In addition, the method includes providing a set of mechanisms for at least one of detection and a recovery from a hardware failure. The method further includes recovering a persistent state of a set of applications. In addition, the method includes maintaining the persistent state across a set of nodes through the hardware failover. In one embodiment, the system may include a WAL interface to persist a state of a distributed system. The system may also include a WAL replication servlet to maintain and/or recover a set of replicas of a WAL.

Abstract: A method comprises determining an aggregate usage of CPU attributable to a given virtual machine (VM), wherein the aggregate usage of CPU attributable to the given VM includes a determined amount of CPU usage by a driver domain, such as by a network driver domain, that is attributable to the given VM. The method further comprises scheduling, by an aggregate proportional-share scheduler, CPU access to the given VM based at least in part on the determined aggregate usage of CPU attributable to the given VM.

Abstract: A method comprises observing communication through a virtualized interface between at least one virtual machine (VM) and a driver domain. The method further comprises determining for each of the at least one VM, based on the observed communication through the virtualized interface, an amount of communication between the VM and the driver domain. In certain embodiments, the method further comprises determining for each of the at least one VM, based on the determined amount of communication between the VM and the driver domain, CPU utilization of the driver domain attributable to the VM. In certain embodiments, the driver domain comprises a network driver domain. In certain embodiments, the driver domain comprises an isolated network diver domain.

Abstract: A method comprises determining an aggregate usage of CPU attributable to a given virtual machine (VM), wherein the aggregate usage of CPU attributable to the given VM includes a determined amount of CPU usage by a driver domain, such as by a network driver domain, that is attributable to the given VM. The method further comprises scheduling, by an aggregate proportional-share scheduler, CPU access to the given VM based at least in part on the determined aggregate usage of CPU attributable to the given VM.

Abstract: A method comprises determining a flexible limit on an amount of resource usage by a driver domain on behalf of a given virtual machine (VM). The method further comprises controlling the resource usage by the driver domain on behalf of the given VM so as not to exceed the flexible limit except under a permitted condition. In certain embodiments the resource usage by the driver domain on behalf of the given VM is controlled so as not to exceed the flexible limit except when a slack share of resource usage is available to the driver domain. Such a slack share of resource usage is a share of resource usage allocated to the driver domain that will not otherwise be used on behalf of another VM.