US Patent 7720864 Expiration of access tokens for quiescing a distributed system

A method, system and computer accessible medium for expiring access tokens in preparation for freezing file images. A metadata server may maintain a next scheduled quiesce time and may issue access tokens configured to expire before the next scheduled quiesce time. A metadata server may set an access token's expiration time to a maximum expiration time indicated by the next scheduled quiesce time or may set an access token's expiration time to a default expiration time if the default expiration time is earlier than the maximum expiration time. A storage device may recognize and enforce the access token's expiration time.