US Patent 7653836 Logging metadata modifications in a data storage system

A method, system, apparatus, and computer-readable medium for logging metadata modifications in a storage system are provided. According to one method, modifications to storage system metadata are detected and described in a log string data structure. The log strings are collected and periodically committed to a mass storage device in the data storage system. The log strings may be collected in a log buffer data structure that includes the collected log strings and one or more unique, constantly increasing timestamps. The time stamps are written at the end of each sector of the log buffer. The log buffer may be committed to the mass storage device when the log buffer is full, when a predefined period of time has elapsed since the previous commitment of the log strings to disk, or in a manner designed to ensure that one write of the log buffer is always outstanding. A logger module is operative to collect the log strings, build the log buffer, and to commit the log buffer to disk.