摘要:
The present invention relates to an apparatus and method for eliminating duplication of a file in a distributed storage system. The apparatus and method for eliminating duplication of a file in a distributed storage system according to the present invention calculates a hash value of each chunk for an active file; calculates a secondary hash value by adding the hash values calculated for respective chunks; examines duplication of the file using the hash value of each chunk and the secondary hash value; and eliminates a duplicated file depending on a result of the examination.
摘要:
The present invention relates to an apparatus and method for managing files in a distributed storage system. The apparatus and method for managing a file in a distributed storage system according to the present invention counts the number of inquiries on a file requested by a client; selects the file as a hot file if the number of inquiries counted in a certain counting period is larger than a hot file selection threshold value; and increases the number of copies of the file selected as a hot file or stores the file selected as a hot file in a storage device having a relatively good performance.
摘要:
The present invention relates to an apparatus and method for managing a file in a distributed storage system. The apparatus and method for managing a file in a distributed storage system calculates a retention time of the file based on at least one of a current time, a file creation time, a file modification time and a recent file inquiry time; selects the file as an archive file if the retention time of the file is larger than a predetermined reference time; and relocates an original file and some or all of copy files of the file selected as an archive file from an active server to an archive server or from an active disk to an archive disk. If the number of inquiries on the file selected as an archive file counted in a counting period is larger than a predetermined threshold value or the file is modified or changed, the original file and some or all of the copy files of the file are restored from the archive sever to the active server or from the archive disk to the active disk
摘要:
The present invention relates to an apparatus and method for managing files in a distributed storage system. The apparatus and method for managing a file in a distributed storage system according to the present invention counts the number of inquiries on a file requested by a client; selects the file as a hot file if the number of inquiries counted in a certain counting period is larger than a hot file selection threshold value; and increases the number of copies of the file selected as a hot file or stores the file selected as a hot file in a storage device having a relatively good performance.
摘要:
Disclosed is an electrolyte for a lithium secondary battery including a non-aqueous organic solvent and alkylphosphonic acid cyclic anhydride of the following Formula (I) where R, R′, and R″ are alkyl groups having 1 to 4 carbon atoms.
摘要:
Disclosed is an active sonar system capable of estimating a direction and a range of a target by using a sound pulse. A target range error can be estimated by the active sonar system, by applying a principle that a sound pulse used to detect an underwater target with consideration of a vertical structure of a sound velocity in water is reflected and refracted through a multipath not a linear path.
摘要:
A non-aqueous electrolyte for a lithium secondary battery is provided. The electrolyte comprises a lithium salt, a non-aqueous solvent, and an organic compound selected from the group consisting of compounds represented by Formulae (1) to (6): wherein R1 to R12 are each independently selected from the group consisting of primary, secondary, and tertiary alkyl groups, alkenyl groups, and aryl groups; X is hydrogen or halogen; and n and m are numerical values ranging from 0 to 3.
摘要:
A non-aqueous electrolyte for a lithium secondary battery is provided. The electrolyte comprises a lithium salt, a non-aqueous solvent, and an organic compound selected from the group consisting of compounds represented by Formulae (1) to (6): wherein R1 to R12 are each independently selected from the group consisting of primary, secondary, and tertiary alkyl groups, alkenyl groups, and aryl groups; X is hydrogen or halogen; and n and m are numerical values ranging from 0 to 3.
摘要:
A rechargeable lithium battery includes a negative electrode including a negative active material, a positive electrode including a positive active material, and an electrolyte including LiPO2F2 and a sultone-based compound.