Abstract: A scheduler selects an I/O from a session of a pool and updates token buckets associated with resource limits and reserves for the session and the pool and statistics used in determining fair sharing. To select an I/O, the scheduler identifies sessions with a non-empty queue, identifies head I/Os in the queues, computes for the head I/O a deadline using session and pool reserve buckets and a release time using session and pool limit buckets, and selects a head I/O with an earliest deadline that is past the release time. If the deadline of the selected candidate head I/O is in the past, the scheduler transfers the selected head I/O to the tail of the storage device queue. Otherwise, the scheduler selects the pool with the least amount of I/O traffic according to a session fair share estimator.

Abstract: Indirect access to local file systems is provided using storage tank protocols, allowing federation of a local file system into a distributed file system while preserving local access to the existing data in the local file system. The goal of the present system is to federate and migrate the data on a computer system with minimum disruption to applications operating on the computer system. Existing applications on a computer system continue to operate during data federation and migration and require little or no reconfiguration either when the data migration starts or when it ends. Data consistency is maintained: existing applications may modify data in the file system during migration or federation. During federation, other computer systems (or hosts) may modify the data in the file system if access control information allows them to do so. All changes in the file system are seen consistently on all hosts.

Abstract: A resource utilization enforcement system enforces resource quotas in a distributed system. A bank on a central server maintains an account for each principal; the account is equivalent to a resource quota for the principal. Quotas are tracked through the use of digital coins that represent resource consumption. The bank is allowed coin generation privileges. At initiation of a computing session, a purse manager on the client accesses the account of the principal and requests coins to exchange for consumed resources. The purse manager manages the coins withdrawn in a “purse” for the principal. The purse manager submits coins to a cashier on the storage device to “purchase” storage for the principal. Refunds are provided if the storage consumption event frees storage.