Storage cluster data structure expansion

Abstract

A method for storage cluster expansion is provided. The method includes distributing user data throughout a storage cluster as directed by each of a plurality of authorities in the storage cluster. Each of the plurality of authorities has a plurality of wards, and each of the plurality of wards has ownership of a range of the user data. The method includes splitting one of the plurality of authorities, as a parent authority, into at least two child authorities and assigning a first subset of the plurality of wards of the parent authority to one of the at least two child authorities, and a second subset of the plurality of wards of the parent authority to another one of the at least two child authorities.

What is claimed is: 
     
         1 . A method, comprising:
 distributing data throughout storage nodes of a storage cluster in cooperation with a plurality of data structures in the storage cluster, wherein respective data structures have ownership of a range of the data;   generating at least two child data structures from one of the plurality of data structures; and   assigning a first subset of the data associated with the one of the plurality of data structures to a first child data structure, and a second subset of the data associated with the one of the plurality of data structures to a second child data structure.   
     
     
         2 . The method of  claim 1 , wherein one of the at least two child data structures remains in a same storage node as the parent data structure. 
     
     
         3 . The method of  claim 1 , further comprising:
 deleting the one of the plurality of data structures.   
     
     
         4 . The method of  claim 1 , wherein the generating is responsive to adding a storage node to the storage cluster. 
     
     
         5 . The method of  claim 1 , further comprising:
 reprocessing metadata of the one of the plurality of data structure into metadata for respective child data structure.   
     
     
         6 . The method of  claim 1 , wherein at least one of the storage nodes comprises a plurality of flash memory devices with differing capacities. 
     
     
         7 . The method of  claim 1 , wherein the generating and the assigning do not require moving the data. 
     
     
         8 . A tangible, non-transitory, computer-readable media having instructions thereupon which, when executed by a processing device, cause the processing device to perform a method comprising:
 distributing data throughout storage nodes of a storage cluster in cooperation with a plurality of data structures in the storage cluster, wherein respective data structures have ownership of a range of the data;   generating at least two child data structures from one of the plurality of data structures; and   assigning a first subset of the data associated with the one of the plurality of data structures to a first child data structure, and a second subset of the data associated with the one of the plurality of data structures to a second child data structure.   
     
     
         9 . The computer readable media of  claim 8 , wherein one of the at least two child data structures remains in a same storage node as the parent data structure. 
     
     
         10 . The computer readable media of  claim 8 , further comprising:
 deleting the one of the plurality of data structures.   
     
     
         11 . The computer readable media of  claim 8 , wherein the generating is responsive to adding a storage node to the storage cluster. 
     
     
         12 . The computer readable media of  claim 8 , further comprising:
 reprocessing metadata of the one of the plurality of data structure into metadata for respective child data structure.   
     
     
         13 . The computer readable media of  claim 8 , wherein at least one of the storage nodes comprises a plurality of flash memory devices with differing capacities. 
     
     
         14 . The computer readable media of  claim 8 , wherein the generating and the assigning do not require moving the data. 
     
     
         15 . A storage cluster, comprising:
 a plurality of storage nodes having storage memory, at least one of the plurality of storage nodes having a processing device configured to perform:
 distribute data throughout storage nodes of a storage cluster in cooperation with a plurality of data structures in the storage cluster, wherein respective data structures have ownership of a range of the data; 
 generate at least two child data structures from one of the plurality of data structures; and 
 assign a first subset of the data associated with the one of the plurality of data structures to a first child data structure, and a second subset of the data associated with the one of the plurality of data structures to a second child data structure. 
   
     
     
         16 . The storage cluster of  claim 15 , wherein one of the at least two child data structures remains in a same storage node as the parent data structure. 
     
     
         17 . The storage cluster of  claim 15 , wherein the processing device is further configured to perform:
 delete the one of the plurality of data structures.   
     
     
         18 . The storage cluster of  claim 15 , wherein the generating is responsive to adding a storage node to the storage cluster. 
     
     
         19 . The storage cluster of  claim 15 , wherein at least one of the storage nodes comprises a plurality of flash memory devices with differing capacities. 
     
     
         20 . The storage cluster of  claim 15 , wherein the generating and the assigning do not require moving the data.