METHOD AND DEVICE FOR RECOVERING CHECKPOINT IN COPY ON WRITE BASED FILE SYSTEM

摘要

Disclosed are a method and device for recovering a checkpoint in a copy on write based file system. The method for recovering a checkpoint comprises: according to a checkpoint recovery instruction, obtaining M data blocks which are allocated between the last checkpoint recovery moment and this checkpoint recovery moment by a file system, where M is an integer which is not smaller than 1, wherein, the M data blocks are data blocks allocated for at least one of a checkpoint and a snapshot which are generated between the last checkpoint recovery moment and this checkpoint recovery moment; conducting a fixed-step addition operation on the number of times that a data block among the M data blocks needing to be reserved is quoted, and determining a first data block needing to be recovered from the M data blocks; determining a second data block needing to be recovered from N data blocks allocated for at least one of a checkpoint and a snapshot which are reserved at the last checkpoint recovery moment, where N is an integer which is not smaller than 1; and recovering the first data block and the second data block.