Data copying method and apparatus in a thin provisioned system
First Claim
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1. A data migration method in a storage system comprising:
- receiving from a host system designation of a source volume, the source volume comprising data for which the data migration will be performed;
receiving from a host system designation of a target volume, the target volume comprising one or more storage segments allocated from a disk device; and
for each logical block address in the source volume, if the logical block address designates an area on the source volume that contains production data, then copying the production data to the target volume,the copying comprising;
allocating a free storage segment from the disk device to the target volume if the logical block address does not designate a storage segment that has been allocated to the target volume; and
associating the logical block address with the allocated free storage segment, the logical block address thereby designating the allocated free storage segment,wherein the allocating and the associating are performed automatically without user involvement, andwherein the target volume comprises physical storage devices contained in an external storage system separate from the storage system, wherein the target volume is identified by the host system by a first identifier, wherein the target volume is identified in the external storage system by a second identifier the method further comprising consulting mapping information that maps the first identifier to the second identifier, wherein the copying uses the second identifier to access the target volume.
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Abstract
Data migration includes copying between normal volumes and thin provisioned volumes. Data in a normal volume can be copied to a thin provisioned volume. Alternatively, data structures can be provided to facilitate converting a normal volume into a thin provisioned volume without actual copying of data. Copying from a thin provisioned volume to a normal volume is also disclosed.
53 Citations
27 Claims
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1. A data migration method in a storage system comprising:
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receiving from a host system designation of a source volume, the source volume comprising data for which the data migration will be performed; receiving from a host system designation of a target volume, the target volume comprising one or more storage segments allocated from a disk device; and for each logical block address in the source volume, if the logical block address designates an area on the source volume that contains production data, then copying the production data to the target volume, the copying comprising; allocating a free storage segment from the disk device to the target volume if the logical block address does not designate a storage segment that has been allocated to the target volume; and associating the logical block address with the allocated free storage segment, the logical block address thereby designating the allocated free storage segment, wherein the allocating and the associating are performed automatically without user involvement, and wherein the target volume comprises physical storage devices contained in an external storage system separate from the storage system, wherein the target volume is identified by the host system by a first identifier, wherein the target volume is identified in the external storage system by a second identifier the method further comprising consulting mapping information that maps the first identifier to the second identifier, wherein the copying uses the second identifier to access the target volume. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A data migration method in a storage system comprising:
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receiving a designation of a source volume, the source volume comprising a plurality of data blocks, each data block having an associated logical block address, some of the data blocks storing data on which the data migration will be performed; receiving a designation of a target volume; defining a plurality of segments on the source volume, each segment comprising one or more of the data blocks; if a segment includes a data block that contains data, then associating the segment with the logical block address of one of its associated data blocks and associating the segment with the target volume, whereby the target volume comprises one or more of the segments, each segment being associated with a logical block address and comprising data; if a segment does not include a data block that contains data, then associating the segment with a list of free segments, wherein associating the segment with a list of free segments is performed automatically without user involvement; and filling locations on the target device with NULL characters which do not correspond to any segments in the source volume. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for a storage system comprising:
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receiving from a host system a write request directed to a first volume; allocating a storage segment from a physical storage device, if the storage segment designated by the logical block address associated with the write request does not exist on the first volume, wherein the determining and the allocating are performed automatically without user involvement; associating the logical block address with the allocated storage segment, wherein data associated with the write request is written to the allocated storage segment; receiving from the host system a designation of a target volume, the target volume being the destination of a migration operation of data stored in the first volume; for each storage segment in the first volume, copying data from the storage segment to a location on the target device that is identified by the logical block address associated with the storage segment; and filling locations on the target device will NULL characters which do not correspond to any storage segments in the first volume. - View Dependent Claims (24, 25, 27)
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26. A method for a storage system comprising:
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receiving from a host system a write request directed to a first volume; allocating a storage segment from a physical storage device, if the storage segment designated by the logical block address associated with the write request does not exist on the first volume, wherein the determining and the allocation are performed automatically without user involvement; associated the location block address with the allocated storage segment wherein data associated with the write request is written to the allocated storage segment; receiving from the host system a designation of a target volume, the target volume being the destination of a migration operation of data stored in the first volume; and for each storage segment in the first volume, copying data from the storage segment to a location on the target device that is identified by the logical block address associated with the storage segment, wherein the target volume comprises physical storage devices contained in an external storage system separate from the storage system, wherein the target volume is identified by the host system by a first identifier, wherein the target volume is identified in the external storage system by a second identifier, the method further comprising consulting mapping information that maps the first identifier to the second identifier, wherein the copying uses the second identifier to access the target volume.
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Specification