Patent ID: 7167880

Claim:
A backup and recovery method for a storage system that avoids journal overflow, the method comprising: producing at least a first snapshot of a data volume, said data volume being configured to receive data by way of write operations issued from a host device; producing a journal entry for each write operation issued from the host device; storing each journal entry in a journal volume, thereby accumulating a list of journal entries; monitoring an amount of free space on the journal volume upon receiving a write operation; stopping the storing of journal entries when the free space falls below a threshold value, thereby avoiding journal overflow, wherein said threshold value includes a first indication of a lowest amount of the free space of capacity of the journal volume; switching to bitmap management by using a bitmap representation of storage areas in the data volume to track the storage areas in the data volume to which the write operations are directed until additional capacity is provided for the journal volume; and storing a new journal entry in the journal volume following adding of capacity by taking a logical snapshot, wherein taking a logical snapshot includes deleting any stored journal entries corresponding in the bitmap to the new journal entry.