Abstract: A stamping assembly includes an upper die, a lower die, first pins and second pins. Each of the upper and lower dies has columns of depressions and columns of guiding holes. Each column of the guiding holes is disposed between two adjacent columns of the depressions. The depressions of one of the upper and lower dies are registered with the guiding holes of another one of the upper and lower dies. The first pins and second pins are respectively positioned in the guiding holes of the upper and lower dies and extend outwardly. The first pins and the second pins are respectively arranged into first and second matrices.

Abstract: A block-based storage system hosts logical volumes that are implemented via multiple replicas of volume data stored on multiple resource hosts in different failure domains. Also, the block-based storage service allows multiple client computing devices to attach to a same given logical volume at the same time. In order to prevent unnecessary failovers, a primary node storing a primary replica is configured with a health check application programmatic interface (API) and a secondary node storing a secondary replica determines whether or not to initiate a failover based on the health of the primary replica.

Abstract: Methods, systems, and computer-readable media for distributed transactions across multiple consensus groups are disclosed. A distributed transaction system comprises a proposer and a plurality of consensus groups, including a first consensus group comprising a first plurality of members and a second consensus group comprising a second plurality of members. The proposer proposes a transaction to at least a portion of the first consensus group and at least a portion of the second consensus group. A majority of the members in the first consensus group agree to perform the transaction, where the transaction is selected from a plurality of proposed transactions involving the first consensus group. A majority of the members in the second consensus group also agree to perform the transaction. The members of the first and second consensus groups perform the transaction to update a plurality of stored replicas.

Abstract: A method for preparing a modular planar interconnect plate for a solid oxide fuel cell includes the steps of: (a) providing a metal blank sheet that includes a main region and a circumferential region; (b) stamping the metal blank sheet to simultaneously form columns of upper protrusions on an upper surface of the main region, columns of lower depressions on a lower surface of the main region, and a front upper retaining protrusion unit and a rear upper retaining protrusion unit on a right side area and a left side area of the circumferential region; (c) stamping the main region to form rows of lower protrusions on the lower surface of the main region and rows of upper depressions on the upper surface of the main region; and (d) forming a pair of upper elongation plates respectively and detachably retained between the front and rear upper retaining protrusion units.

Abstract: Data replication groups may be used to store data in a distributed computing environment. The data replication groups may include a set of nodes executing a consensus protocol to maintain data durably. The nodes of the data replication groups may generate logs containing information corresponding committed operations performed by the nodes. These logs may be collected and processed to obtain useful information corresponding to the operation of the data replication group. Furthermore, this processed information may be provided in the form of a stream to enable event driven operations corresponding to the logs.

Abstract: A block-based storage system hosts logical volumes that are implemented via multiple replicas of volume data stored on multiple resource hosts in different failure domains. Also, the block-based storage service allows multiple client computing devices to attach to a same given logical volume at the same time. In order to prevent unnecessary failovers, a primary node storing a primary replica is configured with a health check application programmatic interface (API) and a secondary node storing a secondary replica determines whether or not to initiate a failover based on the health of the primary replica.

Abstract: A method for preparing a modular planar interconnect plate includes steps of a) providing a metal blank sheet having a main region and two first lateral regions, b) forming two openings respectively in the first lateral regions, and c) stamping to form protrusions and depressions at the main region on lower and upper surfaces of the metal blank sheet. In the stamping step, each of two lower surrounding protrusions and two upper surrounding depressions is formed to surround a corresponding one of the openings, and each of an upper surrounding protrusion and a lower surrounding depression is formed to surround the first lateral regions and the corresponding ones of the protrusions and depressions formed at the main region.

Abstract: A block-based storage system hosts logical volumes that are implemented via multiple replicas of volume data stored on multiple resource hosts in different failure domains. Also, the block-based storage service allows multiple client computing devices to attach to a same given logical volume at the same time. In order to prevent unnecessary failovers, a primary node storing a primary replica is configured with a health check application programmatic interface (API) and a secondary node storing a secondary replica determines whether or not to initiate a failover based on the health of the primary replica.

Abstract: A method for preparing a modular planar interconnect plate includes steps of a) providing a metal blank sheet having a main region and two first lateral regions, b) forming two openings respectively in the first lateral regions, and c) stamping to form protrusions and depressions at the main region on lower and upper surfaces of the metal blank sheet. In the stamping step, each of two lower surrounding protrusions and two upper surrounding depressions is formed to surround a corresponding one of the openings, and each of an upper surrounding protrusion and a lower surrounding depression is formed to surround the corresponding ones of the protrusions and depressions formed at the main region and the first lateral regions.

Abstract: Systems and methods are provided to manage replicas of a virtualized block storage volume. The master replica of the virtualized block storage volume can heartbeat with each secondary replica of the virtualized block storage volume to provide an indication of the status of the master replica. Each secondary replica can reply to the heartbeat of the master replica. Each replica can be configured to request an updated replica configuration based on not receiving a heartbeat from one of the replicas. The master replica can request an updated replica configuration after a first time period without receiving a reply from one of the secondary replicas and each secondary replica can request an updated replica configuration after a second time period without receiving a communication from the master replica. Use of the heartbeat process between the master replica and the secondary replicas can increase system speed or reduce power consumption.

Abstract: A method for preparing a modular planar interconnect plate for a solid oxide fuel cell includes the steps of: (a) providing a metal blank sheet, (b) stamping a main region of the metal blank sheet to form a plurality of columns of upper protrusions on an upper surface of the main region of the metal blank sheet and a plurality of columns of lower depressions on a lower surface of the main region of the metal blank sheet, and (c) stamping the main region of the metal blank sheet to form a plurality of rows of lower protrusions on a lower surface of the main region of the metal blank sheet and a plurality of rows of upper depressions on the upper surface of the main region of the metal blank sheet.

Abstract: A method for preparing a modular planar interconnect plate for a solid oxide fuel cell includes the steps of: (a) providing a metal blank sheet, (b) stamping a main region of the metal blank sheet to form a plurality of columns of upper protrusions on an upper surface of the main region of the metal blank sheet and a plurality of columns of lower depressions on a lower surface of the main region of the metal blank sheet, and (c) stamping the main region of the metal blank sheet to form a plurality of rows of lower protrusions on a lower surface of the main region of the metal blank sheet and a plurality of rows of upper depressions on the upper surface of the main region of the metal blank sheet.

Abstract: A system that hosts computing resources may implement optimistically granting permission to host computing resources. A request for permission to host a computing resource may be received by a control plane. If the control plane determines that the resource host is the first to request permission to host the resource, then the control plane may store an indication of permission that blocks other resource hosts from obtaining permission to host the computing resource and sending an acknowledgement of permission to the resource host that requested permission.

Abstract: A block-based storage system hosts logical volumes that are implemented via multiple replicas of volume data stored on multiple resource hosts in different failure domains. Also, the block-based storage service allows multiple client computing devices to attach to a same given logical volume at the same time. In order to prevent unnecessary failovers, a primary node storing a primary replica is configured with a health check application programmatic interface (API) and a secondary node storing a secondary replica determines whether or not to initiate a failover based on the health of the primary replica.

Abstract: A method for preparing a modular planar interconnect plate for a solid oxide fuel cell includes the steps of: (a) providing a metal blank sheet, (b) stamping a main region of the metal blank sheet to form a plurality of columns of upper protrusions on an upper surface of the main region of the metal blank sheet and a plurality of columns of lower depressions on a lower surface of the main region of the metal blank sheet, and (c) stamping the main region of the metal blank sheet to forma plurality of rows of lower protrusions on a lower surface of the main region of the metal blank sheet and a plurality of rows of upper depressions on the upper surface of the main region of the metal blank sheet.

Abstract: A block-based storage system hosts logical volumes that are implemented via multiple replicas of volume data stored on multiple resource hosts in different failure domains. Also, the block-based storage service allows multiple client computing devices to attach to a same given logical volume at the same time. In order to prevent unnecessary failovers, a primary node storing a primary replica is configured with a health check application programmatic interface (API) and a secondary node storing a secondary replica determines whether or not to initiate a failover based on the health of the primary replica.

Abstract: A block-based storage system hosts logical volumes that are implemented via multiple replicas of volume data stored on multiple resource hosts in different failure domains. Also, the block-based storage service allows multiple client computing devices to attach to a same given logical volume at the same time. A membership group authority authorizes sequence numbers for a given logical volume and an associated membership group. The members of the membership group ensure that the members are in agreement on the latest sequence number for the given logical volume before responding to read or write requests directed to the given logical volume.

Abstract: A method for preparing a modular planar interconnect plate for a solid oxide fuel cell includes the steps of: (a) providing a metal blank sheet, (b) stamping a main region of the metal blank sheet to form a plurality of columns of upper protrusions on an upper surface of the main region of the metal blank sheet and a plurality of columns of lower depressions on a lower surface of the main region of the metal blank sheet, and (c) stamping the main region of the metal blank sheet to forma plurality of rows of lower protrusions on a lower surface of the main region of the metal blank sheet and a plurality of rows of upper depressions on the upper surface of the main region of the metal blank sheet.

Abstract: Data replication groups may be used to store data in a distributed computing environment. The data replication groups may include a set of nodes executing a consensus protocol to maintain data durably. In order to increase the speed of provisioning, a data replication may be provision with less than the total number of nodes to be included in the group. Once an initial set of nodes have been provisioned and are implementing a consensus protocol, the data replication group may begin to receive traffic. Furthermore, new nodes may be added to the group until the total number of nodes for the group has been reached.

Abstract: Data replication groups may be used to store data in a distributed computing environment. A data replication group may include a set of nodes executing a consensus protocol to maintain data durably. In order to increase efficiency and performance of the data replication, a particular node of the data replication group may be assigned the role of master node. The role of master node may be lease in accordance with a consensus protocol. If the lease is not renewed within an interval of time election/selection of a new master node may be commenced.