Abstract: Techniques are disclosed for dynamically rebalancing a caching layer within a distributed database system hosted across a distributed computing environment. In some embodiments, a system that includes a plurality of physical nodes implementing a hosting service deploys containers that serve as caching nodes for the distributed database system. Each container is configured to store cached data within a memory internal to its respective physical node. The system monitors the storage utilization and read/write activity across the caching containers, and based on this monitoring, redistributes data to balance the load across the cluster. Rebalancing can include identifying underutilized and overutilized containers, retrieving subsets of data from overworked containers from persistent storage, and storing the data in underutilized containers.

Abstract: Techniques are disclosed for managing metadata of a distributed database system in a hybrid manner. A computer system may receive, from a computing device, a request to access a set of data stored in nodes of a distributed storage system that is a caching layer of the system. The system retrieves metadata for a set of data specified in the request, including accessing a reversemap storing a reverse-ordered copy of original metadata stored in a metadata store of the system, where the reversemap is stored on durable storage of the system. Based on retrieving the metadata from the reversemap, the system accesses nodes of the distributed storage system, where the reversemap specifies the nodes of the distributed storage system that store the set of data. The system transmits, to the computing device, information indicating a result of accessing data stored in nodes of the distributed storage system.

Abstract: A method for efficient distributed object manager (DOM) owner migration in a virtual storage area network (VSAN) is provided. Embodiments include determining to migrate a DOM owner object from a source DOM owner server to a destination DOM owner server. Embodiments include determining that an input or output (I/O) operation affecting the DOM owner object is in progress. Embodiments include, prior to updating the DOM owner object based on the I/O operation, transferring the DOM owner object from the source DOM owner server to the destination DOM owner server. Embodiments include completing execution of the I/O operation on the destination DOM owner server. Embodiments include updating the DOM owner object on the destination DOM owner server based on the I/O operation.

Abstract: Techniques are disclosed for managing metadata of a distributed database system in a hybrid manner. A computer system may receive, from a computing device, a request to access a set of data stored in nodes of a distributed storage system that is a caching layer of the system. The system retrieves metadata for a set of data specified in the request, including accessing a reversemap storing a reverse-ordered copy of original metadata stored in a metadata store of the system, where the reversemap is stored on durable storage of the system. Based on retrieving the metadata from the reversemap, the system accesses nodes of the distributed storage system, where the reversemap specifies the nodes of the distributed storage system that store the set of data. The system transmits, to the computing device, information indicating a result of accessing data stored in nodes of the distributed storage system.

Abstract: A method for efficient distributed object manager (DOM) owner migration in a virtual storage area network (VSAN) is provided. Embodiments include determining to migrate a DOM owner object from a source DOM owner server to a destination DOM owner server. Embodiments include determining that an input or output (I/O) operation affecting the DOM owner object is in progress. Embodiments include, prior to updating the DOM owner object based on the I/O operation, transferring the DOM owner object from the source DOM owner server to the destination DOM owner server. Embodiments include completing execution of the I/O operation on the destination DOM owner server. Embodiments include updating the DOM owner object on the destination DOM owner server based on the I/O operation.

Abstract: A method for dynamic distributed object manager (DOM) owner migration in a virtual storage area network (VSAN) is provided. Embodiments include determining estimated processor load amounts for a plurality of DOM owner servers based on dispatch latency. Embodiments include determining that a first DOM owner server of the plurality of DOM owner servers has a highest estimated processor load amount of the estimated processor load amounts. Embodiments include determining that a second DOM owner server has a lowest estimated processor load amount of the estimated processor load amounts. Embodiments include determining to migrate a DOM owner object from the first DOM owner server to the second DOM owner server based on a dispatch latency value corresponding to the DOM owner object. Embodiments include migrating the DOM owner object from the first DOM owner server to the second DOM owner server.

Abstract: A monitoring interface, includes logic responsive to a pre-fork event, the pre-fork event responsive to a vfork system call. The pre-fork event includes indicia that identifies a child process to be created in accordance with the vfork system call. A method for controlling the execution of a child process created from a parent process, where the parent process is monitored by a software tool includes, receiving indicia that a vfork system call will be executed by the parent process, suspending execution of the parent process, extracting a process identifier from the indicia of the vfork system call, the process identifier corresponding to a child process to be generated by the parent process when the parent process executes the vfork system call, setting a process monitor thread to observe the child process, and resuming execution of the parent process to enable the parent process to execute past the vfork system call.

Abstract: Methods, computer readable media, systems, and computing devices are provided for controlling execution instances. A method embodiment includes maintaining in a counter of a database, a count associated with a particular number of execution instances of a application registered in the database. The method includes setting for the counter, an upper number associated with a particular number of execution instances of the application allowed to be registered in the database. The method also includes receiving to the database, a request from the application to launch an execution instance of the application. The method further includes transmitting from the database to the application, a response to the request, based on the count and the upper number.

Abstract: A method in a computer for facilitating interaction between an application program and a subsystem is disclosed. The method includes providing a virtual process file system layer. The virtual process file system layer is configured to interact with the subsystem in a substantially content-independent manner. The method additionally includes providing a content dependent module, the content dependent module being associated with the subsystem and is configured interact with the subsystem in a content-dependent manner. The method further includes providing a directory structure table, the directory structure table being configured to track a name of the content dependent module, wherein the content-dependent module is configured to be registered with the directory structure table using a dynamic name.

Abstract: A method in an operating system of a computer for allowing a plurality of application programs to interact with a plurality of subsystems, at least two application programs of the plurality of application programs being associated with two different personalities. The method includes providing a plurality of modules, each of the plurality of modules being associated with at least one personality and configured to interact with one of the plurality of subsystems, at least two modules of the plurality of modules being associated with the two different personalities.

Abstract: A debug interface, includes logic responsive to a pre-fork event, the pre-fork event responsive to a fork instruction call wherein the pre-fork event includes indicia that identifies a child process to be created in accordance with the fork instruction call. A method for controlling the execution of a child process created from a parent process, where the parent process is instrumented by a software tool includes, receiving indicia that a fork instruction will be executed by the parent process, suspending execution of the parent process, extracting a process identifier from the indicia of the fork instruction, the process identifier corresponding to a child process to be generated by the parent process when the parent process executes the fork instruction, setting a process monitor thread to observe the child process, and resuming execution of the parent process to enable the parent process to execute the fork instruction.

Abstract: A method in an operating system of a computer for allowing a plurality of application programs to interact with a plurality of subsystems, at least two application programs of the plurality of application programs being associated with two different personalities. The method includes providing a plurality of modules, each of the plurality of modules being associated with at least one personality and configured to interact with one of the plurality of subsystems, at least two modules of the plurality of modules being associated with the two different personalities.

Abstract: A method in a computer for facilitating interaction between an application program and a subsystem is disclosed. The method includes providing a virtual process file system layer. The virtual process file system layer is configured to interact with the subsystem in a substantially content-independent manner. The method additionally includes providing a content dependent module, the content dependent module being associated with the subsystem and is configured interact with the subsystem in a content-dependent manner. The method further includes providing a directory structure table, the directory structure table being configured to track a name of the content dependent module, wherein the content-dependent module is configured to be registered with the directory structure table using a dynamic name.

Abstract: A file system in a computer is disclosed. The file system is configured to service file access requests between an application program and a first data storage subsystem. The file system includes a first persistent module coupled to receive a first file access request. The first persistent module is associated with the first data storage subsystem. The first file access request pertains to the first data storage subsystem. The file system includes a first transparently unloadable module coupled to the first persistent module to service the first file access request. The first transparently unloadable module is configured to be dynamically unloadable from the computer, wherein the first persistent module includes a blocking arrangement for blocking the first file access request at the first persistent module to allow the first transparently unloadable module to be unloaded without causing an error in the application program.