Data duplication resynchronisation

A method of resynchronising a previous duplication, started at a first time, of a source logical drive on a destination logical drive, the method comprising:

• providing a first snapshot taken at said first time;
• subsequent to said previous duplication, converting said first snapshot such that said first snapshot records only metadata relating to any writes to said source logical drive subsequent to completion of said previous duplication;
• tracking changes made to the data on said source logical drive since said first time using said converted first snapshot;
• starting a resynchronisation duplication operation at a second time later than said first time;
• creating a second snapshot at said second time;
• and
• utilising said first and second snapshots, copying only data which has changed in between said first and second times from said source logical drive to said destination logical drive.

A method of resynchronising a previous duplication, started at a first time, of a source logical drive on a destination logical drive, the method comprising:

• providing first and second snapshots taken at said first time, said first snapshot comprising data and metadata relating to data which has changed since said first time and said second snapshot comprising only metadata relating to data which has changed since said first time;
• subsequent to said previous duplication, deleting said first snapshot;
• tracking, using said second snapshot, changes made to the data on said source logical drive since said first time;
• starting a resynchronisation operation at a second time later than said first time;
• creating a third snapshot at said second time, said third snapshot being arranged to comprise data and metadata relating to data which has changed since said second time;
• utilising said second and third snapshots, copying only data which has changed in between said first and second times from said source logical drive to said destination logical drive.

Apparatus for resynchronising resynchronising a previous duplication, started at a first time, of a source logical drive on a destination logical drive, the apparatus comprising:

• a controller operable to track changes to the data on said source logical drive since said first time;
• and
• to start a resynchronisation operation at a second time later than said first time;
• the controller being further operable to:
• perform said resynchronisation operation by copying data from said source logical drive to said destination logical drive, said controller being operable to copy only data which has changed since said first time.

Apparatus for resynchronising a previous duplication, started at a first time, of a source logical drive on a destination logical drive, the apparatus comprising a controller operable:

• to provide a first snapshot taken at said first time;
• to convert, subsequent to said previous duplication, said first snapshot such that said first snapshot records only metadata relating to any writes to said source logical drive subsequent to completion of said previous duplication;
• to track changes made to the data on said source logical drive since said first time using said converted first snapshot;
• to start a resynchronisation duplication operation at a second time later than said first time;
• to create a second snapshot at said second time;
• and to copy, utilising said first and second snapshots, only data which has changed in between said first and second times from said source logical drive to said destination logical drive.

Apparatus for resynchronising a previous duplication, started at a first time, of a source logical drive on a destination logical drive, the apparatus comprising a controller operable:

• to provide first and second snapshots taken at said first time, said first snapshot comprising data and metadata relating to data which has changed since said first time and said second snapshot comprising only metadata relating to data which has changed since said first time;
• to delete, subsequent to said previous duplication, said first snapshot;
• to track, using said second snapshot, changes made to the data on said source logical drive since said first time;
• to start a resynchronisation operation at a second time later than said first time;
• to create a third snapshot at said second time, said third snapshot being arranged to comprise data and metadata relating to data which has changed since said second time;
• to utilise said second and third snapshots in order to copy, from said source logical drive to said destination logical drive, only data which has changed in between said first and second times.