Modifying A Synchronously Replicated Dataset

Abstract

Modifying a synchronously replicated dataset, including: receiving, by a leader storage system, a request to modify a dataset that is synchronized across a plurality of storage systems; sending, from the leader storage system to a follower storage system, information describing the request to modify the dataset, wherein the leader storage system and the follower storage system each store a copy of the dataset; processing, by the leader storage system on the copy of the dataset that is stored on the leader storage system, the request to modify the dataset; receiving, from the follower storage system, an indication that the follower storage system has processed the request to modify the dataset on the copy of the dataset that is stored on the follower storage system; and acknowledging, by the leader storage system, completion of the request to modify the dataset.

What is claimed is: 
     
         1 . A method comprising:
 receiving, by a leader storage system, a request to modify a dataset that is synchronized across a plurality of storage systems;   sending, from the leader storage system to a follower storage system, information describing the request to modify the dataset, wherein the leader storage system and the follower storage system each store a copy of the dataset;   processing, by the leader storage system on the copy of the dataset that is stored on the leader storage system, the request to modify the dataset;   receiving, from the follower storage system, an indication that the follower storage system has processed the request to modify the dataset on the copy of the dataset that is stored on the follower storage system; and   acknowledging, by the leader storage system, completion of the request to modify the dataset.   
     
     
         2 . The method of  claim 1  wherein the information describing the request to modify the dataset includes ordering information for the request to modify the dataset. 
     
     
         3 . The method of  claim 2  wherein:
 the request to modify the dataset includes a request to take a snapshot of the dataset; and 
 the ordering information for the request to modify the dataset includes an identification of one or more other requests to modify the dataset that are to be included in the content of the snapshot of the dataset. 
 
     
     
         4 . The method of  claim 1  wherein the information describing the request to modify the dataset includes common metadata information associated with the request to modify the dataset. 
     
     
         5 . The method of  claim 1  further comprising sending, from the follower storage system to a leader storage system, an indication that the follower storage system has processed the request to modify the dataset on the copy of the dataset that is stored on the follower storage system. 
     
     
         6 . The method of  claim 1  wherein the plurality of storage systems includes at least three storage systems, including one leader storage system and at least two follower storage systems. 
     
     
         7 . The method of  claim 6  further comprising receiving, by the leader storage system that received the request to modify the dataset, an indication that all follower storage systems have processed the request to modify the dataset. 
     
     
         8 . The method of  claim 1  wherein:
 the request to modify the dataset that is synchronized across the plurality of storage systems is received by the leader storage system from a host computing device, and 
 the leader storage system acknowledges completion of the request to modify the dataset to the host computing device. 
 
     
     
         9 . A storage system that includes a plurality of storage devices, the storage system including a computer processor and a computer memory that includes computer program instructions that, when executed by the computer processor, cause the storage system to carry out the steps of:
 receiving a request to modify a dataset that is synchronized across a plurality of storage systems;   sending, to a follower storage system, information describing the request to modify the dataset, wherein the storage system and the follower storage system each store a copy of the dataset;   processing, on the copy of the dataset that is stored on the storage system, the request to modify the dataset;   receiving, from the follower storage system, an indication that the follower storage system has processed the request to modify the dataset on the copy of the dataset that is stored on the follower storage system; and   acknowledging completion of the request to modify the dataset.   
     
     
         10 . The storage system of  claim 9  wherein the information describing the request to modify the dataset includes ordering information for the request to modify the dataset. 
     
     
         11 . The storage system of  claim 10  wherein the request to modify the dataset includes a request to take a snapshot of the dataset; and
 the ordering information for the request to modify the dataset includes an identification of one or more other requests to modify the dataset that are to be included in the content of the snapshot of the dataset. 
 
     
     
         12 . The storage system of  claim 9  wherein the information describing the request to modify the dataset includes common metadata information associated with the request to modify the dataset. 
     
     
         13 . The storage system of  claim 9  wherein the plurality of storage systems includes at least three storage systems, including one leader storage system and at least two follower storage systems. 
     
     
         14 . The storage system of  claim 13  further comprising computer program instructions that, when executed by the computer processor, cause the storage system to carry out the step of receiving an indication that all follower storage systems have processed the request to modify the dataset. 
     
     
         15 . The storage system of  claim 9  wherein:
 the request to modify the dataset that is synchronized across the plurality of storage systems is received by the leader storage system from a host computing device, and 
 the leader storage system acknowledges completion of the request to modify the dataset to the host computing device. 
 
     
     
         16 . A computer program product disposed on a non-transitory computer readable medium, the computer program product including computer program instructions that, when executed, carry out the steps of:
 receiving a request to modify a dataset that is synchronized across a plurality of storage systems;   sending, to a follower storage system, information describing the request to modify the dataset, wherein the storage system and the follower storage system each store a copy of the dataset;   processing, on the copy of the dataset that is stored on the storage system, the request to modify the dataset;   receiving, from the follower storage system, an indication that the follower storage system has processed the request to modify the dataset on the copy of the dataset that is stored on the follower storage system; and   acknowledging completion of the request to modify the dataset.   
     
     
         17 . The computer program product of  claim 16  wherein the information describing the request to modify the dataset includes ordering information for the request to modify the dataset. 
     
     
         18 . The computer program product of  claim 16  wherein the request to modify the dataset includes a request to take a snapshot of the dataset; and
 the ordering information for the request to modify the dataset includes an identification of one or more other requests to modify the dataset that are to be included in the content of the snapshot of the dataset. 
 
     
     
         19 . The computer program product of  claim 16  wherein the information describing the request to modify the dataset includes common metadata information associated with the request to modify the dataset. 
     
     
         20 . The computer program product of  claim 16  wherein the plurality of storage systems includes at least three storage systems, including one leader storage system and at least two follower storage systems, and the computer program product further comprises computer program instructions that, when executed, carry out the step of receiving an indication that all follower storage systems have processed the request to modify the dataset.