Abstract: A method and apparatus for synchronizing updates to a large set of global counters are described. In one embodiment, the method includes making updates to a global state in response to a file system making changes to data in memory. In parallel, updates are made to a copy of the global state in a temporary buffer in response to the file system flushing the data changes to a mass storage device. The temporary buffer thus includes a set of deltas representing the changes to be made to the global state in response to the changed data in memory being pushed to the mass storage device. The method further includes merging the deltas in the temporary buffer with the global state.

Abstract: Methods of iterating through a set of data objects on a source server, copying them to a destination server, and preparing a mapping database correlating source and destination data object identifiers are described and claimed. The mapping database also includes data retention policy information and policy discrepancy information. Systems using similar methods, and software to perform similar methods, are also described and claimed.