Common Log File System

The job of CLFS, like any other transactional logging system, is to record a series of steps required for some action so that they can be either played back accurately in the future to commit the transaction to secondary storage or undone if required. CLFS first marshals logs records to in-memory buffers and then writes them to log-files on secondary storage (stable media in CLFS terminology) for permanent persistence. When the data will be flushed to stable media is controlled by built-in policies, but a CLFS client application can override that and force a flush. CLFS allows for customizable log formats, expansion and truncation of logs according to defined policies, as well as simultaneous use by multiple client applications. CLFS is able to store log files anywhere on the file system. CLFS defines a device driver interface (DDI), via which physical storage system specific drivers plug into the CLFS API. The CLFS driver implements the ARIES recovery algorithm; other algorithms can be supported by using custom drivers. ==References==