Method and system for ensuring consistence of distributed metadata in cluster file system

Abstract

The invention provides a method for ensuring the operation consistence of distributed metadata in a cluster file system in combination with a local log. The method comprises the following steps of: making a coordinator and a participant record a distributed metadata sub-operation update generated by using distributed metadata sub-operation in the local log as a local transaction, wherein the record of the distributed metadata sub-operation update includes a distributed transaction and / or a distributed metadata update; after the local transaction is submitted, writing the distributed transaction into a distributed log, and writing the distributed metadata update into a metadata disk; and before starting the distributed metadata sub-operation, forcibly submitting a local log transaction. According to the method, the local log is multiplexed effectively, and the implementation complexity of the distributed log is lowered; and moreover, cascading aborts can be avoided.

Description

technical field [0001] The present invention relates to a distributed metadata operation technology of a cluster file system, in particular to a method for ensuring the consistency of distributed metadata in a cluster file system Background technique [0002] In large-scale cluster file systems, the separation of metadata and data services has become a trend. On the one hand, data access does not need to go through the metadata server, but directly accesses the storage device in an out-of-band manner, so as to obtain high data access performance; on the other hand, the metadata server specifically provides metadata services, offloading the data access load, Therefore, a single metadata server can support higher client access performance, manage more storage devices, and support larger system scale expansion. However, with the continuous expansion of the system scale, a single metadata server has gradually become the bottleneck restricting the expansion of the system. In or...

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Problems solved by technology

However, the above problems are not considered in the two-way redundant distributed log method

In addition, in the two-way redundant distributed log method, it is possible that due to the simultaneous downtime of the nodes at both ends, the state of the distributed metadata operation will be undone and restored to a consistent state that has not been executed at all. However, if other metadata servers have subsequent distributed If the type operation depends on the undo distributed metadata operation, it will lead to cascading undo, and all subsequent dependent operations need to be undone. The overhead of cascading undo is high, and there may be cases where undo cannot be completed. Therefore, it is necessary to ensure that multiple There will be no cascading undo between distributed metadata operations to ensure that the system can recover to a consistent state

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