Patent ID: 6269382
Filing Date: 2001-07-31
Classification: G06F,Y10S

Abstract:
In a system having access to both a local and a remote storage medium, wherein migration policies are used to migrate data from the local storage medium to the remote storage medium, a method of pre-migrating the data prior to fully migrating the data in a manner such that the data can be rapidly deleted from the local storage medium and migrated when migration policies associated with the data are satisfied, said method comprising the steps of:obtaining parameters that specify migration policies under which data is to be migrated from the local storage medium to the remote storage medium such that, when the data is migrated, the data exists at the remote storage medium and does not exist at the local storage medium;identifying a first file stored on the local storage medium that has not yet satisfied the migration policies and is not yet eligible for migration from thc local storage medium to the remote storage medium according to the migration policies;even though the migration policies have not yet been satisfied, pre-migrating data in said first file to the remote storage medium so that the pre-migrated data exists on the local storage medium and also exists on the remote storage medium prior to said first file satisfying the migration policies;prior to said first file satisfying the migration policies, receiving a request to write incoming data to the local storage medium, the local storage medium not having sufficient free space to store the incoming data without deleting data already stored at the local storage medium;determining whether a second file that (1) contains other pre-migrated data, and (2) has satisfied the migration policies, exists on the local storage medium;if said second file exists, migrating said second file from the local storage medium to the remote storage medium so as to create said sufficient free space; andif said second file does not exist, migrating said first file from the local storage medium to the remote storage medium to create said sufficient free space notwithstanding said first file not yet satisfying the migration policies.