Electronics and Telecommunications Research Institute

Myung Hoon Cha

Hong Yeon Kim

Young Kyun Kim

Wan Gyun Choi

June Hwan Kim

Sang-Min Lee

Myung Joon Kim

Han Namgoong

A distributed storage server includes a plurality of data server devices and a plurality of metadata server devices. The metadata server devices store metadata associated with data which is distributively stored in the data server devices. A selected metadata server device checks whether a dangling directory occurs by performing a rename operation, based on information associated with a full path of a parent directory of a source and a full path of a parent directory of a target included in a request of the rename operation. When it is determined that the dangling directory does not occur, the selected metadata server device processes transactions directed to the metadata such that the rename operation is performed. The checking whether the dangling directory occurs is performed before a transaction period for processing the transactions.

Distributed storage server, server device included therein, and method of operating server device

A distributed file system includes metadata servers and data servers. The metadata server includes a selecting unit to select a data server from the data servers, a chunk allocation requesting unit to request that the selected data server perform chunk allocation, a chunk list managing unit to insert a list of chunks transmitted from the data server into a chunk list pool and determine an arrangement method of the chunk list pool, and a chunk fetching unit to fetch available chunk information from the chunk list pool. The data server includes a receiving unit to receive request for chunk allocation from the metadata server, a chunk allocating unit to allocate chunks in response to the request for chunk allocation and write a list of chunks based on information about the allocated chunk, and a transmitting unit to transmit the list of chunks to the metadata server.

Distributed file system and method of creating files effectively

Disclosed are an apparatus, a system, and a method for recovering meta data using fragmentary information. The system for recovering meta data includes: a data server storing recovery information for recovering at least one data file and meta data related to each of the data file; and a meta data server storing the meta data related to the data files and receiving the recovery information from the data server when the meta data are lost to recover the lost meta data. By this configuration, the exemplary embodiment of the present invention stably can the lost meta data of the meta data server by using the recovery the meta data and prevent the phenomenon that the meta data collides with each other on the same directory hierarchical structure.

Apparatus, system and method for recovering meta data using fragmentary information

A file storage system, a file storing method, and a file searching method. In the file storing method, a single file to be stored is classified into at least one or more objects, and the classified objects are classified into pages with a serial number. One storage device to record the file is selected among a plurality of storage devices connected through a network. One object is allocated to the selected storage device. Pages configuring the file of the object allocated to the selected storage device are stored. When all pages of the file are not stored, the remaining pages are stored by allocating new object to a new storage device. Metadata for managing information about the storage of the file is set. Accordingly, the file can be stored over several disks. In addition, the overall system performance can be increased by setting the file information in the object metadata simply using the least resources.

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Daejeon, South Korea

Myung Hoon Cha