Electronics and Telecommunications Research Institute

Bum Joo Shin

Gyoung Bae Kim

Young Ho Kim

Chang Soo Kim

Chang-Soo Kim

Dong Jae Kang

Yu Hyeon Bak

Yong Ju Lee

Yong-Ju Lee

Myung Joon Kim

Choon Seo Park

Yuhyeon Bak

Seon-Yeong Park

A journaling method is provided for supporting a recovery when a system is abnormally terminated in a shared disk environment. When a system call operation to take part in a journaling is generated, in order to guarantee a recovery, a transaction is started and new transaction region is assigned. Then, a system is initialized and a transaction type is set up. Lock information on modified data is acquired and added to the transaction so that a transaction manages lock information. A reflection to a disk during a modification of metadata is prevented. Modified metadata added to the transaction and modified information on principal general data are recorded. Then, lock information connected to the transaction is released.

Journaling and recovery method of shared disk file system

An efficient snapshot technique based on a mapping for a large logical volume shared in multiple hosts. According to the present invention, problems of time delays in a conventional snapshot technique is solved by employing a FAB and an SSB, which are bits representing whether a COW operation is carried out to a mapping entry. In other words, the present invention solves the problems of delaying a write operation of corresponding volume, which is simultaneously executed when a snapshot is created, until the snapshot creation is completed.

System and method of an efficient snapshot for shared large storage

The present invention relates to the method for managing directories of a large-scale file system. The present invention the steps of creating root blocks which have a fixed global depth, calculating an index value which shows the location information on how many bits will be referenced for root blocks from the global depth through a hash function when root blocks are completely filled with directories, calculating the block numbers of leaf blocks consisted of extent blocks based on a plurality fixed length platform which are logical and successive objects using the index value and storing the block numbers sequentially to the root blocks, and storing the directory entries of root blocks separately in leaf blocks. As a result, the present invention can improve the search performance by minimizing the cause of frequently change of data storage structure of the file system and flexibly preventing creation of indirect blocks.

Method for managing directories of large-scale file system

A system having RAID levels includes a storage medium, a memory and a CPU. The storage medium has at least two disks. The memory stores a striping zone information table of total disks in which a physical address of data recorded in a disk of the storage medium is converted into a logic address. The CPU modifies a striping zone information table stored in the memory in case a new disk is added to the storage medium, stores the modified striping zone information table in the memory, converts a logic address of data to be written/read out from the stored table into a physical address in response to the disk writing/reading instructions, searches positions of a corresponding disk D and a physical block B and controls writing or reading out data.

Raid system and mapping method thereof

Disclosed is a coherence preservation method of duplicated data in RAID subsystem. The method comprises the steps of: if a read operation is requested by the RAID subsystem, selecting an arbitrary target disk among disks having duplicated data, and implementing the read operation on the selected disk; implementing a read error handling to determine whether an error occurs in the disks selected upon the read operation, and if the error occurs in the read operation of the selected target disk, repeating the read error handling until the read operation of the data succeeds by circulating the remaining metering-treated disks in turns; after the read error handling, if the read operation on the remaining disk in all succeeds, completing the read error handling, and if the read operation on the remaining disk in all fails, returning the error to the disk, and completing the read error handling; if a write operation is requested by the RAID subsystem, implementing the write operation on the disks having duplicated data; after implementing the write operation, if a temporary error occurs in the duplicated data, implementing a temporary error handling to maintain the data coherence in the disks having the duplicated data and to recover the temporary error; and after implementing the write operation, if a permanent error occurs in the duplicated data, implementing a permanent error handling to maintain the data coherence in the disks having the duplicated data and to recover the permanent error.

Coherence preservation method of duplicated data in RAID subsystem

A method for managing a logical volume for minimizing a size of metadata and supporting dynamic online resizing and software redundant array of independent disks (RAID), and a computer-readable recording medium storing instructions for embodying the method, are disclosed. The method includes the metadata having a disk partition table containing information of a disk partition in which the metadata is stored; a logical volume table for maintaining the information of the logical volume by storing duplicated information of the logical volume onto all disk partitions of the logical volume; an extent allocation table for indicating whether each extent in the disk partitions is used or not; and a mapping table for maintaining a mapping information for a physical address space corresponding to a logical address space which is a continuous address space equal in size of storage space of whole logical volume.

Method for managing logical volume in order to support dynamic online resizing and software raid and to minimize metadata and computer readable medium storing the same

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Taejon, South Korea

Bum Joo Shin