Recovery of a logical unit in a consistency group while replicating other logical units in the consistency group
First Claim
Patent Images
1. A method comprising:
- recovering at least one logical unit of a consistency group in a journal-based replication system without interruption of replication of other logical units in the consistency group, the at least one logical unit being one of a physical logical unit or a virtual logical unit;
receiving a request to recover a logical unit in the consistency group at a point-in-time (PIT);
ceasing replication of the logical unit to a backup logical unit;
recovering the logical unit at the PIT while continuing replicating other logical units in the CG;
marking a first recovery point at an end portion of an UNDO METADATA stream associated with the PIT;
marking a second recovery point at an end portion of a DO METADATA stream associated with the PIT; and
generating differences between the production logical unit and the backup logical unit by joining the metadata in a local delta marker stream and the data in the DO metadata stream associated with the production logical unit.
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Abstract
In one aspect, a method includes recovering at least one logical unit of a consistency group in a journal-based replication system without interruption of replication of other logical units in the consistency group, the at least one logical unit being one of a physical logical unit or a virtual logical unit.
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Citations
11 Claims
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1. A method comprising:
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recovering at least one logical unit of a consistency group in a journal-based replication system without interruption of replication of other logical units in the consistency group, the at least one logical unit being one of a physical logical unit or a virtual logical unit; receiving a request to recover a logical unit in the consistency group at a point-in-time (PIT); ceasing replication of the logical unit to a backup logical unit; recovering the logical unit at the PIT while continuing replicating other logical units in the CG; marking a first recovery point at an end portion of an UNDO METADATA stream associated with the PIT; marking a second recovery point at an end portion of a DO METADATA stream associated with the PIT; and generating differences between the production logical unit and the backup logical unit by joining the metadata in a local delta marker stream and the data in the DO metadata stream associated with the production logical unit. - View Dependent Claims (2, 3)
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4. A method comprising:
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recovering at least one logical unit of a consistency group in a journal-based replication system without interruption of replication of other logical units in the consistency group, the at least one logical unit being one of a physical logical unit or a virtual logical unit; receiving a request to recover a logical unit in the consistency group at a point-in-time (PIT); ceasing replication of the logical unit to a backup logical unit; recovering the logical unit at the PIT while continuing replicating other logical units in the CG; marking a first recovery point at an end portion of an UNDO METADATA stream associated with the PIT; marking a second recovery point at an end portion of a DO METADATA stream associated with the PIT; reading data from a write transaction entry in a DO stream; determining if the write transaction entry is between the first recovery point and the second recovery point; and discarding the write transaction entry if the write transaction entry is between the first recovery point and the second recovery point; and if the write transaction entry is not between the first recovery point and the second recovery point; reading data from an UNDO stream for the backup logical unit; writing the UNDO data read from the logical unit to the UNDO stream of the production logical unit; and applying the write transaction read from the DO stream to the backup logical unit, if the entry is to a device different than the recovered device.
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5. An article comprising:
a non-transitory machine-readable medium that stores executable instructions, the instructions causing a machine to; recover at least one logical unit of a consistency group in a journal-based replication system without interruption of replication of other logical units in the consistency group, the at least one logical unit being one of a physical logical unit or a virtual logical unit; receive a request to recover a logical unit in the consistency group at a point-in-time (PIT); cease replication of the logical unit to a backup logical unit; recover the logical unit at the PIT while continuing replicating other logical units in the CG; mark a first recovery point at an end portion of an UNDO METADATA stream associated with the PIT; mark a second recovery point at an end portion of a DO METADATA stream associated with the PIT; and generate differences between the production logical unit and the backup logical unit by joining the metadata in a local delta marker stream and the data in the DO metadata stream associated with the production logical unit. - View Dependent Claims (6, 7)
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8. An apparatus, comprising:
circuitry configured to; recover at least one logical unit of a consistency group in a journal-based replication system without interruption of replication of other logical units in the consistency group, the at least one logical unit being one of a physical logical unit or a virtual logical unit; receive a request to recover a logical unit in the consistency group at a point-in-time (PIT); cease replication of the logical unit to a backup logical unit; and recover the logical unit at the PIT while continuing replicating other logical units in the CG; mark a first recovery point at an end portion of an UNDO METADATA stream associated with the PIT; mark a second recovery point at an end portion of a DO METADATA stream associated with the PIT; and generate differences between the production logical unit and the backup logical unit by joining the metadata in a local delta marker stream and the data in the DO metadata stream associated with the production logical unit. - View Dependent Claims (9, 10, 11)
Specification