Data copying method and apparatus in a thin provisioned system

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.

1 - 2 . (canceled) 
   
   
       3 . A storage system comprising:
 a first port for receiving commands from a host;   a second port for transferring data and commands to a plurality of storage devices;   a processor; and   a memory storing programs,   wherein said programs control a plurality of virtual devices, for which allocations from a pool are performed in response to a write operation,   wherein said programs manage a plurality of logical devices, of which segments are allocated to said plurality of storage devices and are associated with logical block addresses, where said plurality of logical devices present a logical storage area for a logical unit to store and present data to and from said host,   wherein said programs process a first migration from a first virtual device of said plurality of virtual devices to a first logical device of said plurality of logical devices, and   wherein when said programs process said first migration, a pair is created between said first virtual device and said first logical device, and data stored in said first virtual device is copied to a portion of said first logical device.   
   
   
       4 . The storage system according to  claim 3 ,
 wherein said plurality of logical devices are defined by an administrator, and mapping between said plurality of logical devices and parity groups is stored in said memory, and   wherein in response to write operations, if a target of the write operation has not been allocated a storage segment, a storage segment is allocated from said pool before the write operation is performed.   
   
   
       5 . The storage system according to  claim 4 ,
 wherein remainder of said portion of said first logical device not copied is filled by “0,” if the first logical device is not formatted.   
   
   
       6 . The storage system according to  claim 3 ,
 wherein said programs process a second migration from a second logical device of said plurality of logical devices to a second virtual device of said plurality of virtual devices, and   wherein when said programs process said second migration, a copy pair is created between said second logical device and said second virtual device.   
   
   
       7 . The storage system according to  claim 6 ,
 wherein said plurality of logical devices are associated with a bitmap, and said bitmap indicates whether blocks within said plurality of logical devices have stored data or not, and   wherein during said second migration, said bitmap is checked and copy is performed from said second logical device to said second virtual device using said bitmap.   
   
   
       8 . The storage system according to  claim 7 ,
 wherein if said bitmap indicates that there is no stored data, copy is not executed against corresponding region of said second logical device to said second virtual device.   
   
   
       9 . The storage system according to  claim 3 ,
 wherein when said second migration is performed, a bitmap is created for said first logical device.   
   
   
       10 . The storage system according to  claim 3 ,
 wherein said plurality of storage devices are external to said storage system,   wherein said plurality of storage devices are magnetic disks, and   wherein said migrations are recommended or scheduled based on a usage level of each logical device or each virtual device.   
   
   
       11 . A method for controlling a storage system, comprising a first port coupled to a host, a second port coupled to a plurality of storage devices, a processor, and a memory, the method comprising:
 providing a plurality of thin-provisioned volumes to said host, wherein in response to a write operation, storage segments for said plurality of thin-provisioned volumes are allocated from a pool;   managing a plurality of logical devices, of which segments are allocated to said plurality of storage devices and are associated with logical block addresses, wherein said plurality of logical devices present a logical storage area for a logical unit to store and present data to and from said host; and   performing a first migration from a first thin-provisioned volume of said plurality of thin-provisioned volumes to a first logical device of said plurality of logical devices,   wherein when performing said first migration, a pair is created between said first thin-provisioned volume and said first logical device, and data stored in said first thin-provisioned volume is copied to a portion of said first logical device.   
   
   
       12 . The method according to  claim 11 ,
 wherein said plurality of logical devices are defined by an administrator, and mapping between said plurality of logical devices and parity groups is stored in said memory, and   wherein in response to write operations, if a target of the write operation has not been allocated a storage segment, a storage segment is allocated from said pool before the write operation is performed.   
   
   
       13 . The method according to  claim 12 ,
 wherein remainder of said portion of said first logical device not copied is filled by “0,” if the first logical device is not formatted.   
   
   
       14 . The method according to  claim 11 ,
 wherein said programs process a second migration from a second logical device of said plurality of logical devices to a second thin-provisioned volume of said plurality of thin-provisioned volumes, and   wherein when said programs process said second migration, a copy pair is created between said second logical device and said second thin-provisioned volume.   
   
   
       15 . The method according to  claim 14 ,
 wherein said plurality of logical devices are associated with a bitmap, and said bitmap indicates whether blocks within said plurality of logical devices have stored data or not, and   wherein during said second migration, said bitmap is checked and copy is performed from said second logical device to said second thin-provisioned volume using said bitmap.   
   
   
       16 . The method according to  claim 15 ,
 wherein if said bitmap indicates that there is no stored data, copy is not executed against corresponding region of said second logical device to said second thin-provisioned volume.   
   
   
       17 . The method according to  claim 11 ,
 wherein when said second migration is performed, a bitmap is created for said first logical device.   
   
   
       18 . The method according to  claim 11 ,
 wherein said plurality of storage devices are magnetic disks, and   wherein said migrations are recommended or scheduled based on a usage level of each logical device or each thin-provisioned volume.