Hitachi, Ltd.

Lin Wujuan

Shoji Kodama

Kenta Shiga

In a system of local DHT overlays, each has KVS nodes, including one super node. The super nodes organize a global DHT overlay. Each super node maintains Bloom filters of keys in its local DHT overlay for all key ranges. To obtain data corresponding to a key from other local DHT overlays, a super node sends a request to a node which is responsible for the key range hashed from the specified key. The responsible node determines local DHT overlays which may have data corresponding to the key according to Bloom filters registered in the super nodes of the local DHT overlays, updated and converted from counting filters. Requests are sent to the super nodes of the local DHT overlays identified by the responsible node. Thus, requests are not needlessly sent to super nodes of local DHT overlays which do not have data corresponding to the key, thereby reducing traffic.

Traffic reduction method for distributed key-value store

A DHT-based global namespace (GNS) is constructed for a network system that includes network attached storage (NAS) devices, including at least one DHT-NAS device (a NAS device having DHT Functionalities) and at least one Existing-NAS device (a NAS device lacking DHT Functionalities). In a DHT Overlay Construction Phase, the DHT-NAS devices construct a DHT overlay. In an Initial Phase, the GNS is created above share folders in the Existing-NAS devices, with mapping of the share folders in the Existing-NAS devices to GNS paths distributed to a key lookup table in the DHT-NAS devices. Each mapping in the key lookup table includes a key, a GNS path, NAS type, IP address of the NAS, and the path within the NAS Share. There is no central GNS mapping table. In a Discovery Phase, the DHT-NAS devices discover the Existing-NAS devices to construct the GNS under the share folders. In a Working Phase, the DHT-NAS devices service GNS requests.

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Singapore, Singapore

Lin Wujuan