Abstract: The disclosure is directed to moving an application, e.g., a messenger service in a social networking application, to various locations in a distributed computing system, e.g., to improve an efficiency of the application. For example, the application can be moved to a data center that is closer to a location of a user to decrease a latency associated with accessing the application. In another example, the application can be moved to a data center that is closer to a location of a storage system that stores data associated with the application to improve a throughput of the application, e.g., a rate at which data is read and/or written.

Abstract: Processing a file system operation is disclosed. An indication of a desired operation of a distributed file system is received. A metadata node for the desired operation is identified. It is indicated to the identified metadata node to process the desired operation. In the event the identified metadata node becomes not fully functional before the processing by the identified metadata node is confirmed, the distributed file system is analyzed to determine whether to indicate again to process the desired operation.

Abstract: The disclosure is directed to a failover mechanism for failing over an application service, e.g., a messaging service, from servers in a first region to servers in a second region. Data is stored as shards in which each shard contains data associated with a subset of the users. Data access requests are served by a primary region of the shard. A global shard manager manages failing over the application service from a current primary region to a secondary region of the shard. A leader service in the application service replicates data associated with the application service from the primary to the secondary region, and ensures that the state of various other services of the application service in the secondary region is consistent. The leader service confirms that there is no replication lag between the primary and secondary regions and fails over the application service to the secondary region.

Abstract: The disclosure is directed to moving an application, e.g., a messenger service in a social networking application, to various locations in a distributed computing system, e.g., to improve an efficiency of the application. For example, the application can be moved to a data center that is closer to a location of a user to decrease a latency associated with accessing the application. In another example, the application can be moved to a data center that is closer to a location of a storage system that stores data associated with the application to improve a throughput of the application, e.g., a rate at which data is read and/or written.

Abstract: The disclosure is directed to a failover mechanism for failing over an application service, e.g., a messaging service, from servers in a first region to servers in a second region. Data is stored as shards in which each shard contains data associated with a subset of the users. Data access requests are served by a primary region of the shard. A global shard manager manages failing over the application service from a current primary region of a shard to a secondary region of the shard. The current primary determines whether a criterion for failing over, e.g., a replication lag between the primary and the secondary regions is within a threshold, and if it is within the threshold, the failover process waits until the lag is zero. After the replication lag is zero, the application service is failed over to the second region, which then becomes the primary for the shard.

Abstract: Switching an active metadata node is disclosed. An indication that a standby metadata node of a distributed file system should replace an active metadata node of the distributed file system as a new active metadata node of the distributed file system is received. The standby metadata node is included in a server. A request that indicates that the standby metadata node would like to become an exclusive metadata node writer of a transaction log is sent. A confirmation that the standby metadata node is the exclusive metadata node writer of the transaction log is received. Based at least in part on the confirmation, an update that the standby metadata node has become the new active metadata node of the distributed file system is provided.

Abstract: A method and system for reducing replication factor in a file system are provided. In some embodiments, two or more requested files may be grouped together under a leaf directory for RAID process. All data under the directory are grouped into one or more data stripes, each of which comprises a plurality of data blocks. One or more parity data blocks may be generated for each data stripe according to a computing algorithm, such as an exclusive OR (XOR) code or a Reed-Solomon (RS) code. Parity blocks corresponding to the one or more data stripes are concatenated into one parity file. Data blocks of the two or more requested files and their corresponding parity blocks are stored in separate partitions and/or separate storage drives of the file system.

Abstract: A method and system for reducing replication factor in a file system are provided. In some embodiments, two or more requested files may be grouped together under a leaf directory for RAID process. All data under the directory are grouped into one or more data stripes, each of which comprises a plurality of data blocks. One or more parity data blocks may be generated for each data stripe according to a computing algorithm, such as an exclusive OR (XOR) code or a Reed-Solomon (RS) code. Parity blocks corresponding to the one or more data stripes are concatenated into one parity file. Data blocks of the two or more requested files and their corresponding parity blocks are stored in separate partitions and/or separate storage drives of the file system.

Abstract: Switching an active metadata node is disclosed. An indication that a standby metadata node of a distributed file system should replace an active metadata node of the distributed file system as a new active metadata node of the distributed file system is received. The standby metadata node is included in a server. A request that indicates that the standby metadata node would like to become an exclusive metadata node writer of a transaction log is sent. A confirmation that the standby metadata node is the exclusive metadata node writer of the transaction log is received. Based at least in part on the confirmation, an update that the standby metadata node has become the new active metadata node of the distributed file system is provided.

Abstract: Processing a file system operation is disclosed. An indication of a desired operation of a distributed file system is received. A metadata node for the desired operation is identified. It is indicated to the identified metadata node to process the desired operation. In the event the identified metadata node becomes not fully functional before the processing by the identified metadata node is confirmed, the distributed file system is analyzed to determine whether to indicate again to process the desired operation.