Method and apparatus for data recovery using storage based journaling

Abstract

A storage system maintains a journal and a snapshot of one or more data volumes. Two journal entry types are maintained, an AFTER journal entry and a BEFORE journal entry. Two modes of data recovery are provided: “fast” recovery and “undo-able” recovery. A combination of both recovery modes allows the user to quickly recover a targeted data state.

1 . A method for processing data in a data store comprising: 
 obtaining a snapshot of a data store;    updating the snapshot with one or more first after-journal entries; and    after updating the snapshot with one or more first after-journal entries, performing one or more subsequent updates of the snapshot with one or more second after-journal entries, each subsequent update of the snapshot including: 
 storing a before-journal entry; and  
 after storing the before-journal entry, applying one of the second after-journal entries to the snapshot,  
 wherein the subsequent updates of the snapshot can be undone.  
   
     
     
         2 . The method of  claim 1  further comprising, after performing one or more subsequent updates, applying one or more before-journal entries to the snapshot, wherein one or more updates of the snapshot by the second after-journal entries can be undone.  
     
     
         3 . The method of  claim 2  further comprising receiving information indicative of an undo request, and in response thereto performing the step of applying one or more before-journal entries to the snapshot.  
     
     
         4 . The method of  claim 1  wherein the number of first after-journal entries is determined based on a user-provided target time.  
     
     
         5 . The method of  claim 1  wherein the second after-journal entries are applied in increasing order of time.  
     
     
         6 . The method of  claim 1  wherein the step of updating the snapshot with one or more first after-journal entries includes further updating the snapshot with one or more additional after-journal entries, wherein the step of further updating is performed in response to receiving information indicative of a fast recovery request.  
     
     
         7 . The method of  claim 1  wherein the step of obtaining a snapshot includes making a copy of the snapshot on the data store, wherein the updating steps are performed on the copy of the snapshot stored on the data store.  
     
     
         8 . The method of  claim 1  further comprising receiving information indicative of a user-specified data store, wherein the step of obtaining a snapshot includes making a copy of the snapshot on the user-specified data store, wherein the updating steps are performed on the copy of the snapshot stored on the user-specified data store.  
     
     
         9 . A data processing device comprising: 
 a data store;    a controller;    a data storage component configured to store after-journal entries and before-journal entries, and further configured to provide access to the after-journal entries and the before-journal entries,    the controller configured to access the data store and to access the data storage component,    the controller further configured to perform the method steps of  claim 1 .    
     
     
         10 . A method for processing data comprising: 
 obtaining a snapshot of at least a portion of a data store;    applying a plurality of first after-journal entries to update the snapshot, including receiving a first time indication from a user, the number of first after-journal entries being based on the first time indication;    providing access to the snapshot so that the user can access the snapshot;    receiving a recovery mode indication and a second time indication from the user;    applying a plurality of second after-journal entries to further update the snapshot, the number of second after-journal entries being based on the second time indication; and    if the recovery mode indication is indicative of an undo-able recovery mode, then for each second after-journal entry, taking a before-journal entry of the snapshot before applying the second after-journal entry to the snapshot.    
     
     
         11 . The method of  claim 10  further comprising receiving a third time indication from the user and applying one or more before-journal entries to the snapshot, the number of before-journal entries that are applied to the snapshot being dependent on the third time indication.  
     
     
         12 . A data processing system comprising: 
 a host component comprising at least one host processing unit;    a storage component comprising at least one storage control unit;    first program control means contained in the host component for controlling operation of the host processing unit; and    second program control means contained in the storage component for controlling operation of the storage control unit,    the first program control means and the second program control means further for operating, respectively, the host processing unit and the storage control unit to perform the method steps of  claim 10 .    
     
     
         13 . The data processing system of  claim 12  wherein the first program control means comprises first program code and the second program control means comprises second program code.  
     
     
         14 . A method for processing data on a data store comprising: 
 receiving input from a user indicative of a first data volume;    receiving input from the user indicative of a second data volume;    obtaining a snapshot of at least a portion of the first data volume;    storing the snapshot on the second data volume;    a first step of updating the snapshot with a plurality of first after-journal entries;    providing user-access to the second data volume;    receiving a first indication from the user, wherein if the first indication is indicative of a fast recovery operation, then repeating the first step of updating the snapshot with a plurality of second after-journal entries; and    subsequent to the first step of updating, a second step of updating the snapshot with a plurality of third after-journal entries, including for each third after-journal entry taking a before-journal entry of the snapshot prior to updating the snapshot with the third after-journal entry,    the first, second, and third after-journal entries being representative of write operations previously performed on the first data volume.    
     
     
         15 . The method of  claim 14  further comprising receiving input from the user indicative of a target time wherein the number of first after-journal entries is based on the target time.  
     
     
         16 . The method of  claim 15  further comprising receiving input from the user indicative of a refined target time wherein the number of second after-journal entries is based on the refined target time.  
     
     
         17 . The method of  claim 15  further comprising receiving input from the user indicative of a refined target time wherein the number of third after-journal entries is based on the refined target time.  
     
     
         18 . The method of  claim 14  further comprising applying one or more before-journal entries to the snapshot to undo snapshot updates produced by the application of one or more of the third after-journal entries.  
     
     
         19 . The method of  claim 14  further comprising receiving a second indication from the user and in response thereto, applying one or more before-journal entries to the snapshot to undo snapshot updates produced by the application of one or more of the third after-journal entries.  
     
     
         20 . The method of  claim 19  further comprising receiving input from the user indicative of a time, wherein the number of before-journal entries is based on the time.  
     
     
         21 . The method of  claim 19  wherein the one or more before-journal entries are applied sequentially beginning with the most recent before-journal entry.  
     
     
         22 . The method of  claim 14  wherein the first data volume and the second data volume refer to the same data volume, wherein the snapshot represents a data state of at least a portion of the first data volume at a first point in time.  
     
     
         23 . The method of  claim 14  wherein the first data volume is a production volume and the second data volume refers to a data volume different from the production volume.