US 8,555,019 B2Granted

Using a migration cache to cache tracks during migration

AssigneeInternational Business Machines Corporation

InventorsDavid Montgomery, Todd C. Sorenson

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Abstract

Provided are a method, system, and computer program product for using a migration cache to cache tracks during migration. Indication is made in an extent list of tracks in an extent in a source storage subject to Input/Output (I/O) requests. A migration operation is initiated to migrate the extent from the source storage to a destination storage. In response to initiating the migration operation, a determination is made of a first set of tracks in the extent in the source storage indicated in the extent list. A determination is also made of a second set of tracks in the extent. The tracks in the source storage in the first set are copied to a migration cache, wherein updates to the tracks in the migration cache during the migration operation are applied to the migration cache. The tracks in the second set are copied directly from the source storage to the destination storage without buffering in the migration cache. The tracks in the first set are copied from the migration cache to the destination storage. The migration operation is completed in response to copying the first set of tracks from the migration cache to the destination storage and copying the second set of tracks from the source storage to the destination storage, wherein after the migration the tracks in the extent are located in the destination storage.

Claims20

Dependent claims

A computer program product for migrating data from a source storage to a destination storage, the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that executes to perform operations, the operations comprising:

indicating in an extent list tracks in an extent in the source storage subject to Input/Output (I/O) requests;
initiating a migration operation to migrate the extent from the source storage to the destination storage;
and
in response to initiating the migration operation, performing:
determining a first set of tracks in the extent in the source storage indicated in the extent list based on an access characteristic of the tracks in the extent;
determining a second set of tracks in the extent, wherein the second set of tracks have the access characteristic to a lesser extent than the first set of tracks;
copying the tracks in the source storage in the first set to a migration cache, wherein updates to the tracks in the migration cache during the migration operation are applied to the migration cache;
copying the tracks in the second set directly from the source storage to the destination storage without buffering in the migration cache;
copying the tracks in the first set from the migration cache to the destination storage;
and
completing the migration operation in response to copying the first set of tracks from the migration cache to the destination storage and copying the second set of tracks from the source storage to the destination storage, wherein after the migration the tracks in the extent are located in the destination storage.

8 more elements

A system for migrating data from a source storage to a destination storage, comprising:

a computer memory;
a migration manager executed to perform operations, the operations comprising:
indicating in an extent list in the computer memory tracks in an extent in the source storage subject to Input/Output (I/O) requests;
initiating a migration operation to migrate the extent from the source storage to the destination storage;
and
in response to initiating the migration operation, performing:
determining a first set of tracks in the extent in the source storage indicated in the extent list based on an access characteristic of the tracks in the extent;
determining a second set of tracks in the extent, wherein the second set of tracks have the access characteristic to a lesser extent than the first set of tracks;
copying the tracks in the source storage in the first set to a migration cache in the computer memory, wherein updates to the tracks in the migration cache during the migration operation are applied to the migration cache;
copying the tracks in the second set directly from the source storage to the destination storage without buffering in the migration cache;
copying the tracks in the first set from the migration cache to the destination storage;
and
completing the migration operation in response to copying the first set of tracks from the migration cache to the destination storage and copying the second set of tracks from the source storage to the destination storage, wherein after the migration the tracks in the extent are located in the destination storage.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/877,956Filed 8 Sep 2010
Published: US 2012/0059994 A18 Mar 2012
Granted: 8 Oct 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G06F 12/0868
For peripheral storage systems, e.g. disk cache: data transfer between cache memory and other subsystems, e.g. storage devices or host systems
G06F 3/0617
Improving the reliability of storage systems: in relation to availability
G06F 3/0647
Horizontal data movement in storage systems, i.e. moving data in between storage devices or systems: migration mechanisms
G06F 3/0685
Plurality of storage devices: hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays