Method and apparatus for backup and recovery using storage based journaling
First Claim
Patent Images
1. A method for processing data in an application data store comprising:
- producing at least a first snapshot of an application data store, the application data store 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 data store, thereby accumulating a list of journal entries;
monitoring an amount of free space on the journal data store; and
when the free space falls below a first threshold value, then removing one or more journal entries from the journal data store, thereby increasing the free space, wherein enough of the journal entries are removed so that the free space rises above a second threshold value.
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Abstract
A storage system maintains a journal of journal entries and at lease one snapshot of one or more data volumes. By assigning a unique sequence number to journal and snapshot, it is easy to find a journal which can be applied to the snapshot. A technique is described for detecting an overflow condition of running out of journal space and recovering the journal space.
106 Citations
1 Claim
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1. A method for processing data in an application data store comprising:
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producing at least a first snapshot of an application data store, the application data store 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 data store, thereby accumulating a list of journal entries;
monitoring an amount of free space on the journal data store; and
when the free space falls below a first threshold value, then removing one or more journal entries from the journal data store, thereby increasing the free space, wherein enough of the journal entries are removed so that the free space rises above a second threshold value.
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Specification