Wandisco Inc.

Cirata, Inc.

Ramakrishna Thurimella

Yeturu Aahlad

Christopher Mackey

Michal Dobisek

Naeem Akthar

A computer-implemented method may comprise receiving proposals to mutate a data stored in a distributed and replicated file system coupled to a network, the distributed and replicated data system comprising a plurality of nodes, each comprising a server. A metadata service maintains and updates a replica of a namespace of the distributed and replicated file system and coordinates updates to the data by generating an ordered set of agreements corresponding to the received proposals, the ordered set of agreements specifying an order in which the nodes are to mutate data stored in data nodes and cause corresponding changes to the state of the namespace. For each agreement in the generated ordered set of agreements, a corresponding writers list may be provided that comprises an ordered list of nodes to execute the agreement and make corresponding changes to the namespace. The ordered set of agreements may then be sent to the plurality of nodes along with, for each agreement in the ordered set of agreements, the corresponding writers list or a pre-generated index thereto and each of the plurality of nodes may be configured to only execute agreements for which it is a first-listed node on the received writers list.

Methods, devices and systems for writer pre-selection in distributed data systems

A computer-implemented method of migrating metadata from a donor filesystem D having a rooted tree structure to a beneficiary filesystem B while processing commands that operate on the metadata may comprise, while a command to operate on the metadata is not received, replicating the donor filesystem D at the beneficiary filesystem B by sequentially copying metadata of nodes of the donor filesystem D to the beneficiary filesystem B. When a command is received to operate on the metadata, the command may be executed at both the donor filesystem D and the beneficiary filesystem B when all arguments of the command are present in both the donor filesystem D and the beneficiary filesystem B. When none of arguments are present in the beneficiary filesystem B, the command may be executed at the donor filesystem D only. When only some of the arguments are present in the beneficiary filesystem B, the command may be enqueued at least until all arguments of the command are present in the beneficiary filesystem B. When all arguments thereof are present in the beneficiary filesystem B, the enqueued commands may be dequeued and scheduled for execution.

Methods, devices and systems for migrating an active filesystem

A distributed system that implements an online exchange may comprise a plurality of server nodes, each of which being configured to receive exchange transaction proposals from customers of the online exchange over a computer network and each being configured to store a copy of a blockchain distributed ledger of completed exchange transactions. A consensus engine may be coupled, over the computer network, to the plurality of server nodes and may receive a plurality of exchange transaction proposals from the plurality of server nodes. The consensus engine may be being further configured to achieve consensus on the plurality of exchange transaction proposals and to generate, in response, an ordering of agreed-upon exchange transaction proposals that includes the plurality of exchange transaction proposals on which consensus has been reached. This ordering of agreed-upon exchange transaction proposals is identically provided to each of the server nodes and specifies the order in which the server nodes are to execute exchange transactions and to update their copy of the distributed ledger. The ordering of agreed-upon exchange transaction proposals may optionally be re-ordered and identically provided to each server node to conform to the local orderings at the exchange transaction proposal's node server of origin.

Methods, devices and systems for a distributed coordination engine-based exchange that implements a blockchain distributed ledger

A distributed system that implements an online exchange may comprise a plurality of server nodes, each of which being configured to receive exchange transaction proposals from customers of the online exchange over a computer network and each being configured to store a copy of a blockchain distributed ledger of completed exchange transactions. A distributed coordination engine may be coupled, over the computer network, to the plurality of server nodes and may receive a plurality of exchange transaction proposals from the plurality of server nodes. The distributed coordination engine may be being further configured to achieve consensus on the plurality of exchange transaction proposals and to generate, in response, an ordering of agreed-upon exchange transaction proposals that includes the plurality of exchange transaction proposals on which consensus has been reached. This ordering of agreed-upon exchange transaction proposals is identically provided to each of the server nodes and specifies the order in which the server nodes are to execute exchange transactions and to update their copy of the distributed ledger. The ordering of agreed-upon exchange transaction proposals may optionally be re-ordered and identically provided to each server node to conform to the local orderings at the exchange transaction proposal's node server of origin.

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San Francisco, CA, United States of America

Ramakrishna Thurimella