METHODS AND SYSTEMS FOR MANAGEMENT OF COPIES OF A MAPPED STORAGE VOLUME
First Claim
1. A method for managing copies of a mapped storage volume in a storage system having a plurality of physical blocks with each physical block having a corresponding physical block address, the method comprising:
- generating a first copy of a mapped storage volume comprising a plurality of logical blocks each mapped to a corresponding physical block;
copying the first copy to generate a second copy of the mapped storage volume;
associating ancestral meta-data with the first copy and with the second copy to identify an ancestral relationship between the first copy and the second copy;
associating reference meta-data with each physical block, wherein the reference meta-data indicates which copies of the mapped storage volume may access a corresponding physical block; and
executing a write request that modifies content of an identified logical block of an identified copy of the mapped storage volume, wherein the identified logical block is associated with a corresponding identified physical block, wherein the execution is based on a function of the ancestral meta-data associated with the identified copy and the reference meta-data associated with the identified physical block, and wherein the execution assures other copies of the mapped storage volume retain access to the original content of the identified physical block as it exists prior to the execution of the write request.
9 Assignments
0 Petitions
Accused Products
Abstract
Methods and systems for rapid creation of copies of a mapped storage volume. A new copy of a mapped storage volume is created by copying the mapping table and updating meta-data associated with the new copy and any ancestral parents thereof. The physical blocks remain untouched when creating a new copy as does any meta-data associated with the physical blocks. Rather, reference meta-data associated with each physical block is updated only in response to processing of a write request to an identified block of an identified copy of the mapped storage volume. Thus copy creation is rapid as compared to prior techniques reliant on reference counters.
-
Citations
17 Claims
-
1. A method for managing copies of a mapped storage volume in a storage system having a plurality of physical blocks with each physical block having a corresponding physical block address, the method comprising:
-
generating a first copy of a mapped storage volume comprising a plurality of logical blocks each mapped to a corresponding physical block; copying the first copy to generate a second copy of the mapped storage volume; associating ancestral meta-data with the first copy and with the second copy to identify an ancestral relationship between the first copy and the second copy; associating reference meta-data with each physical block, wherein the reference meta-data indicates which copies of the mapped storage volume may access a corresponding physical block; and executing a write request that modifies content of an identified logical block of an identified copy of the mapped storage volume, wherein the identified logical block is associated with a corresponding identified physical block, wherein the execution is based on a function of the ancestral meta-data associated with the identified copy and the reference meta-data associated with the identified physical block, and wherein the execution assures other copies of the mapped storage volume retain access to the original content of the identified physical block as it exists prior to the execution of the write request. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A storage system comprising:
-
a plurality of physical storage devices comprising a plurality of physical blocks; and a storage controller coupled to the plurality of storage devices and adapted to define one or more copies of a mapped storage volume, each copy of the mapped storage volume comprising a plurality of logical blocks each logical block mapped to a corresponding physical block of the plurality of physical blocks, the controller further comprising; ancestral meta-data associated with each copy of the mapped storage volume and indicating ancestral relationships between said each copy of the mapped storage volume and other copies of the mapped storage volume; and reference meta-data associated with each physical block and defining which of the multiple copies of the mapped storage volume may reference the associated physical block, wherein the controller is adapted to update the ancestral meta-data of each copy having an ancestral relationship with a new copy when the new copy of the mapped storage volume is created, and wherein the controller is adapted to process a received write request affecting an identified physical block of an identified copy based on the ancestral meta-data of one or more copies of the mapped storage volume and based on the reference meta-data associated with the identified physical block. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
-
-
16. A method for managing copies of a mapped storage volume in a storage system, the storage system comprising a storage controller and a plurality of storage devices each having a plurality of physical blocks, the method comprising:
-
creating a copy of the mapped storage volume from a previous copy of the mapped storage volume; updating ancestral meta-data for the copy, the previous copy, and any parental ancestor copies of the previous copy to indicate the ancestral relationship among the multiple copies; and processing a write request to an identified physical block in an identified copy wherein the step of processing further comprises; determining from reference meta-data associated with identified copy whether any other copies having an ancestral relationship with the identified copy may access the identified physical block; and responsive to a determination that another copy may access the identified physical block, performing the additional steps of; writing data supplied in the write request to a new physical block in the storage devices; updating reference meta-data associated with the new physical block to indicate that the identified copy may access the new physical block; and updating reference meta-data associated with the identified physical block to indicate that the identified copy no longer can no longer access the identified physical block. - View Dependent Claims (17)
-
Specification