Microsoft Technology Licensing, LLC

Huisheng Liu

Guhan Suriyanarayanan

Nikolaj Skallerud Bjorner

Dan Teodosiu

Nikolaj S Bjørner

David C Steere

Shobana Balakrishnan

Muthukaruppan Annamalai

Patrick E Bozeman

Michael J Bohlander

Nikolaj S Bjerner

Aspects of the subject matter described herein relate to resource replication systems. In aspects, a mechanism is described that detects when local resources are stale. Local resources may be stale when the time between a last successful synchronization activity and a current time exceeds a staleness value. If the local resources are determined to be stale, the local member may refrain from certain synchronization activities until the local member is allowed to resume these certain synchronization activities. If the local resources are not stale, additional synchronization activities including synchronizing resources between the member and an upstream or downstream partner may be performed.

Resource freshness and replication

Various embodiments introduce the notion of a replication entity which implements a highly scalable file replication system. In one embodiment, the replication entity resides in the form of a scalable replication service. In at least some embodiments, the replication service provides a 'drive in the sky' facility that can be used by individuals, such as subscribers, to synchronize their individual machines, such that their files are automatically replicated to a safe and always-on location. Alternatively or additionally, individuals such as subscribers can also access their files via a web-based interface when they are away from their machines.

Scalable file replication and web-based access

Aspects of the subject matter described herein relate to replicating initial content in resource replication systems. In aspects, each member participating in a replica group obtains a content set state from a directory service. The content set state indicates whether the member is allowed to synchronize resources with another member participating in the replica group. If the member is designated as a primary member, the member may replicate out resources to its downstream partners. If a member is not designated as a primary member, the member may not replicate out resources to its downstream partners until it has successfully synchronized resources with an upstream partner. Fence values may be set which control which resources win (and are replicated out) during synchronization.

Pre-existing content replication

Aspects of the subject matter described herein relate to shutdown recovery for resource replication systems. In aspects, a mechanism is described in which a machine having replicated data thereon can recover from a dirty shutdown. First, the machine determines whether a dirty shutdown has occurred. If so, the machine automatically performs shutdown recovery by causing resource metadata stored by the machine to be consistent with resource data stored by the machine. This may involve fixing the resource metadata for updates to the resource data that were not flushed to disk or may involve deleting the resource metadata and restoring it from another machine replicating the data.

Shutdown recovery

Aspects of the subject matter described herein relate to resource replication systems. In aspects, a mechanism is described that maintains replicated resources on a slave member that participates in a replica group. The slave member detects that a local resource has been updated locally. If the resource was created locally in the update, the slave member deletes the local resource. Otherwise, the slave member determines an upstream partner from which to install a replacement resource and then installs the replacement resource. In aspects, this behavior undoes local updates to local resources that occur on the slave member.

Growing community of inventors

Sammamish, WA, United States of America

Huisheng Liu