Abstract: A non-disruptive upgrade (NDU) technique involves installing and activating a first copy of a new version of an application in a temporary directory to (i) obtain control from an original version of the application while the original version is installed in an application directory and (ii) shut down the original version. The technique further involves, after the first copy of the new version obtains control from the original version and the original version is shut down, installing and activating a second copy of the new version of the application in the application directory to (i) obtain control from the first copy of the new version while the first copy of the new version is installed in the temporary directory and (ii) shut down the first copy of the new version. Such operation maintains the continuity of work at each phase of the NDU technique.

Abstract: Systems and methods maintain cache coherency between storage controllers utilizing bitmap data. In one embodiment, a storage controller processes an I/O request for a logical volume from a host, and generates one or more cache entries in a cache memory that is based on the request. The storage controller identifies a backup storage controller for managing the logical volume, and generates bitmap data that identifies cache entries in the cache memory that have changed since synchronizing with the backup storage controller. The storage controller provides the bitmap data to the backup storage controller to allow the backup storage controller to synchronize its cache memory with the cache memory of the storage controller based on the bitmap data.

Abstract: Various embodiments implement agents as dynamically linked libraries to run within host processes controlled by an executable agent manager. The agent manager runs as a service or daemon continuously after being loaded into the memory of a computer system. Information concerning agents that are configured to carry out tasks on the computer system is stored in a database accessible to the agent manager. When a task that a particular agent is configured to carry out needs to be done, the agent manager assigns an executable host process to run the agent. The agent manager then sends start and stop commands to the host process to load and halt the agent, respectively.