Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Disclosed is a coherence preservation method of duplicated data in RAID subsystem.

Abstract: The present invention relates to 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. Further, in the write operation carried out after the snapshot creation, an operation of determining whether the COW operation is carried out is achieved by reading only an original mapping block by using the FAB and the SSB, without reading out the snapshot mapping block.

Abstract: 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.

Abstract: 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.

Abstract: Disclosed is a coherence preservation method of duplicated data in RAID subsystem.

Abstract: 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.

Abstract: A RAID subsystem to distributively store data in a disk array having a plurality of disk drives and performing an I/O of the data in parallel is provided. A sparing disk drive stores a recovery image in which recovery information on a block of an error disk drive is recorded. A disk array controller retrieves the recovery information recorded in the recovery image according to a data input/output request of a host computer to check whether the block of the error disk drive is recovered or not. The regenerated block in the block of the sparing disk drive is recorded according to the check result on the block. The recovery information on the regenerated block is recorded in the recovery image.

Abstract: 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.

Abstract: A method for managing a logical volume for minimizing a size of metadata and supporting dynamic online resizing, computer-readable recoding medium storing a program or data structure for embodying the method are disclosed.