Abstract: According to an embodiment there is provided a method for handling requests in a storage system including a plurality of storage nodes connected to each other via a communications network. A first storage node of the plurality of storage nodes may store a reference to a set of at least one collection object stored in the storage system. Each collection object of the set may include at least one of a reference to another collection object stored in the storage system and a reference to at least one data file stored in the storage system. The method may include receiving a first request at the first storage node. The first storage node, for each collection object of the set, may send a second request to a storage node storing the collection object. According to a second aspect there is also provided a storage node.

Abstract: A method and device for maintaining data in a data storage system, comprising a plurality of data storage nodes, the method being employed in a storage node in the data storage system and comprising: monitoring and detecting, conditions in the data storage system that imply the need for replication of data between the nodes in the data storage system; initiating replication processes in case such a condition is detected, wherein the replication processes include sending multicast and unicast requests to other storage nodes, said requests including priority flags, receiving multicast and unicast requests from other storage nodes, wherein the received requests include priority flags, ordering the received requests in different queues depending on their priority flags, and dealing with requests in higher priority queues with higher frequency than requests in lower priority queues.

Abstract: The present invention relates to a distributed data storage system comprising a plurality of storage nodes. Using unicast and multicast transmission, a server application may write data in the storage system. When writing data, at least two storage nodes are selected based in part on a randomized function, which ensures that data is sufficiently spread to provide efficient and reliable replication of data in case a storage node malfunctions.

Abstract: A method for maintaining a data storage system is disclosed. The method may include monitoring a first data storage node. The method may also include detecting a condition regarding the first data storage node, and the condition may indicate that at least one file stored on the first data storage node is to be replicated. The method may also include updating a replication list based on detecting the condition, and the replication list may include an identification of the at least one file and priority information for replication of the at least one file. The method may include performing a data replication procedure based on the replication list, where the data replication procedure may include sending a first multicast message to a plurality of other data storage nodes requesting identification of a second data storage node that maintains a copy of the at least one file.

Abstract: A method for maintaining a data storage system is disclosed. The method may include monitoring for receipt of a first broadcast message from a first data storage node, where the first broadcast message may indicate that the first data storage node is operating correctly. The method may also include detecting that the first data storage node is malfunctioning based on not receiving the first broadcast message for a predetermined period of time. The method may also include initiating a data replication procedure based on detecting that the first data storage node is malfunctioning. The data replication procedure may include sending a first multicast message to a plurality of data storage nodes requesting identification of a second data storage node that maintains a copy of a file stored on the first data storage node.

Abstract: The present invention relates to a distributed data storage system comprising a plurality of storage nodes. Using unicast and multicast transmission, a server application may read and write data in the storage system. Each storage node may monitor reading and writing operations on the system as well as the status of other storage nodes. In this way, the storage nodes may detect a need for replication of files on the system, and may carry out a replication process that serves to maintain a storage of a sufficient number of copies of files with correct versions at geographically diverse locations.