Abstract: Provided are a method, system and article of manufacture, wherein a plurality of broadcast messages are sent from at least one node of a plurality of nodes of a network. A node is discovered based on a received message. An entry is stored, wherein the entry corresponds to the node and a timestamp that indicates a time at which the node was last discovered. A notification is made that the node is offline, in response to determining that a predetermined time has elapsed since the timestamp was last updated.

Abstract: A technique for enabling a client to access the resources of different servers without having specific knowledge of which server has which resources. The client generates multiple copies of a request that identifies an operation to be performed, such as a copy type operation. The client sends a copy of the request to each server. The server determines whether the operation requires access to the server's associated data storage resource. If it does, the server accesses the resource to perform the operation, and sends a corresponding response to the client. Different servers can work on different operations specified in a request. The client receives and merges the responses from the servers. During a failure of one cluster in a multi-cluster system, the surviving cluster can process a request using the resources owned by the failed cluster.

Abstract: A technique for facilitating communication between a client and server using the command pattern. The command pattern is an object-oriented design pattern that describes a pattern for encapsulating instructions and data into a single object, called a command. A client host uses the command pattern to encapsulate instructions and first data into a command object, and provides the command object to a server host. The server host executes the instructions in the command object to provide second data, based on the first data, in the command object, and returns the command object with the second data to the client host. The server host may provide the command object with a reference to a resource, such as a database, for providing the second data. The command object is a single object. The client host interprets the second data in the returned command object.

Abstract: A technique for reducing the number of events that are transmitted by a server to a client in a client/server application programming interface (API). At the server host, each of different event messages is associated with at least one event category in a hierarchy of event categories. Each client host sends a registration request to the server host to inform the server host that the client host wants to receive only event messages that are associated with a specified event category. The server host associates the specified event category with each client host, and communicates only the event messages that are descendants of the specified event category.

Abstract: A user interface facilitates copying data between storage resources, such as servers. A user selects a source storage resource and a target storage resource. Available adapters are displayed through which a path can be established between the selected source and target storage resources. The user selects at least one of the available adapters to configure the path to copy data from the selected source storage resource to the selected target storage resource. The list of available adapters is dynamically updated so that only currently available adapters are displayed. The displayed adapters may be further limited to those that are compatible with a certain path type selected by the user, such as adapters used for a unidirectional or a bi-directional path.

Abstract: A technique for determining whether a server host supports the functions in a command sent by a client host. The client host formulates a command including a command object that contains parameter objects. The parameter objects, which represent the functions, are serialized, e.g., using the Java serialization command, and communicated to the server host. The server host attempts to deserialize the parameter objects. If it is successful, it is concluded that the server host supports the functions represented by the parameter objects. Or, it is concluded that the server host is incompatible with the functions represented by one or more parameter objects that cannot be deserialized. The server host may be a storage server, and the functions may be storage-related, such as a copy type to be performed.