Data storage system having data restore by swapping logical units

Abstract

This invention is a system and method for managing replication of data distributed over one or more computer systems. A data storage system can perform computer-executed steps of establishing one or more mirrored copies of data that are copies of one or more volumes of standard data (e.g. a database) on a first computer system. In one embodiment, the mirrored data is restored using logical volume swapping.

What is claimed is:  
     
         1 . A method of performing a data restore by swapping logical units, comprising: 
 providing a first logical unit in a storage array to a client;    creating a mirror of the first logical unit on a second logical unit of the storage array;    splitting the mirror from the first logical unit; and    providing the second logical unit to the client without notifying the client such that the client can access the mirrored data.    
     
     
         2 . The method according to  claim 1 , further including recreating the first logical unit from the second logical unit.  
     
     
         3 . The method according to  claim 1 , further including 
 restoring the mirrored data from the second logical unit to the first logical unit; and    returning client access to the first logical unit.    
     
     
         4 . The method according to  claim 3 , further including waiting for synchronization of the mirror of the second logical unit.  
     
     
         5 . The method according to  claim 3 , further including determining characteristics of a physical storage device corresponding to the first logical unit.  
     
     
         6 . The method according to  claim 5 , wherein the storage device characteristics include world wide name and subsystem name.  
     
     
         7 . The method according to  claim 1 , further including creating the mirror of the first logical unit in a format selected from the group consisting of JBOD, RAID  0 , RAID  0 +1, and RAID  1 .  
     
     
         8 . The method according to  claim 1 , further including selecting the second logical unit from a plurality of logical units in the storage array based on visibility to the client.  
     
     
         9 . The method according to  claim 1 , further including converting a host physical device location to an identification of the first logical unit.  
     
     
         10 . The method according to  claim 9 , further including unmounting a filesystem associated with the first logical unit.  
     
     
         11 . The method according to  claim 10 , further including disabling client access to the first logical unit.  
     
     
         12 . The method according to  claim 1 , wherein the storage array corresponds to one of a Symmetrix™ system, a Clarion™ system, and an HSG80 ™ system.  
     
     
         13 . A data storage system, comprising computer-executable logic that enables the method steps of: 
 providing a first logical unit in a storage array to a client;    creating a mirror of the first logical unit on a second logical unit of the storage array;    splitting the mirror from the first logical unit; and    providing the second logical unit to the client without notifying the client such that the client can access the mirrored data.    
     
     
         14 . The system according to  claim 13 , further including recreating the first logical unit from the second logical unit.  
     
     
         15 . The system according to  claim 13 , further including 
 restoring the mirrored data from the second logical unit to the first logical unit; and    returning client access to the first logical unit.    
     
     
         16 . The system according to  claim 15 , further including waiting for synchronization of the mirror of the second logical unit.  
     
     
         17 . The system according to  claim 5 , further including determining characteristics of a physical storage device corresponding to the first logical unit.  
     
     
         18 . The system according to  claim 17 , wherein the storage device characteristics include world wide name and subsystem name.  
     
     
         19 . The system according to  claim 13 , further including creating the mirror of the first logical unit in a format selected from the group consisting of JBOD, RAID  0 , RAID  0 +1, and RAID  1 .  
     
     
         20 . The system according to  claim 13 , further including selecting the second logical unit from a plurality of logical units in the storage array based on visibility to the client.  
     
     
         21 . The system according to  claim 13 , further including converting a host physical device location to an identification of the first logical unit.  
     
     
         22 . The system according to  claim 21 , further including unmounting a filesystem associated with the first logical unit.  
     
     
         23 . The system according to  claim 22 , further including disabling client access to the first logical unit.  
     
     
         24 . The system according to  claim 13 , further including creating a map of logical information on the first logical unit to one or more physical devices.  
     
     
         25 . The system according to  claim 1 , wherein the storage array corresponds to one of a Symmetrix™ system, a Clarion™ system, and an HSG80™ system.  
     
     
         26 . A computer readable medium for use with a data storage system comprising code to enable the steps of: 
 providing a first logical unit in a storage array to a client;    creating a mirror of the first logical unit on a second logical unit of the storage array;    splitting the mirror from the first logical unit; and    providing the second logical unit to the client without notifying the client such that the client can access the mirrored data.    
     
     
         27 . The medium according to  claim 26 , further including 
 restoring the mirrored data from the second logical unit to the first logical unit; and    returning client access to the first logical unit.