Data management system with shortcut migration via efficient automatic reconnection to previously migrated copy

• US 6,434,682 B1
• Filed: 09/28/2000
• Issued: 08/13/2002
• Est. Priority Date: 09/28/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Ashton, Lyn Lequam, Kissinger, Stanley Mark, Pence, Jerry Wayne
• Primary Examiner(s): KIM, HONG CHONG
• Application Number:
  US09/672,068
• Time in Patent Office: 684 Days
• Field of Search: 711/162, 711/161, 711/165, 711/112, 711/111, 714/6
• US Class Current: 711/162
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays

Abstract

A data management system responds to migration requests by automatically invoking a shortcut migration process for suitable candidates. Suitability of candidate data is efficiently evaluated using, among other considerations, the presence or absence of an expedited access indicator for the data which is previously set when the data is recalled from backup storage. In the shortcut migration process, the system automatically reconnects a previously migrated copy of the data object, if available.

Claims

1. An automated, computer-driven method for operating a data management system comprising direct-access storage constituting a primary level of storage and multiple removable data storage media constituting an auxiliary level of storage, the system including an inventory containing metadata identifying data objects contained in the auxiliary level, comprising operations of:

responsive to each recall request comprising a request to copy a target data object from the auxiliary level to the primary level, performing recall operations comprising;

determining whether the target data object meets prescribed future-reconnection criteria, and if so, updating a catalog to include an expedited access indicator associated with the target data object;

copying the target data object from the auxiliary level to the primary level;

updating the inventory to invalidate metadata identifying the target data object in the auxiliary level;

responsive to migration requests each comprising a request to copy a specified data object from the primary level to the auxiliary level, performing migration operations comprising;

determining whether the catalog contains an expedited access indicator associated with the specified data object;

if the catalog contains an expedited access indicator associated with the specified data object, determining whether restoration of a copy of the specified data from the auxiliary level is possible, and

if restoration is not possible, performing a full migration comprising copying contents of the specified data object from the primary level to the auxiliary level;

if restoration is possible, performing a shortcut migration comprising updating the inventory to restore invalidated metadata identifying the specified data object in the auxiliary level without copying the specified data object from the primary level to the auxiliary level; and

if the catalog does not contain an expedited access indicator associated with the specified data object, copying content of the specified data object from the primary level to the auxiliary level.

2. The method of claim 1, the operations further comprising:

using historical data to predict future migration requests for data objects having invalidated metadata; and

preserving invalidated metadata in the inventory for sufficient time to satisfy at least some of the predicted future migration requests.

3. The method of claim 1, where the operations further comprise:

according to a prescribed expiration schedule, cleaning the inventory by removing invalidated metadata.

4. The method of claim 2, further responsive to each recall request comprising a request to copy a target data object from the auxiliary level to the primary level, establishing the prescribed expiration schedule for inventory metadata identifying the target data object based upon access history of the target data object.

5. The method of claim 1, where the operation of determining whether the target data object meets the prescribed future-reconnection criteria, and if so, updating the catalog to include the expedited access indicator comprises:

updating the catalog to include the expedited access indicator associated with the target data object unless the target data object meets certain disqualifying criteria.

6. A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations to manage a data management system comprising direct-access storage constituting a primary level of storage and multiple removable data storage media constituting an auxiliary level of storage, the system including an inventory containing metadata identifying data objects contained in the auxiliary level, the operations comprising:

responsive to each recall request comprising a request to copy a target data object from the auxiliary level to the primary level, performing recall operations comprising;

determining whether the target data object meets prescribed future-reconnection criteria, and if so, updating a catalog to include an expedited access indicator associated with the target data object;

copying the target data object from the auxiliary level to the primary level;

updating the inventory to invalidate metadata identifying the target data object in the auxiliary level;

responsive to migration requests each comprising a request to copy a specified data object from the primary level to the auxiliary level, performing migration operations comprising;

determining whether the catalog contains an expedited access indicator associated with the specified data object;

if the catalog contains an expedited access indicator associated with the specified data object, determining whether restoration of a copy of the specified data from the auxiliary level is possible, and

if restoration is not possible, performing a full migration comprising copying contents of the specified data object from the primary level to the auxiliary level;

if restoration is possible, performing a shortcut migration comprising updating the inventory to restore invalidated metadata identifying the specified data object in the auxiliary level without copying the specified data object from the primary level to the auxiliary level; and

if the catalog does not contain an expedited access indicator associated with the specified data object, copying content of the specified data object from the primary level to the auxiliary level.

7. The medium of claim 6, the operations further comprising:

using historical data to predict future migration requests for data objects having invalidated metadata;

preserving invalidated metadata in the inventory for sufficient time to satisfy at least some of the predicted future migration requests.

8. The medium of claim 6, where the operations further comprise:

according to a prescribed expiration schedule, cleaning the inventory by removing invalidated metadata.

9. The medium of claim 7, the operations further comprising, responsive to each recall request comprising a request to copy a target data object from the auxiliary level to the primary level, establishing the prescribed expiration schedule for inventory metadata identifying the target data object based upon access history of the target data object.

10. The medium of claim 6, where the operation of determining whether the target data object meets the prescribed future-reconnection criteria, and if so, updating the catalog to include the expedited access indicator comprises:

updating the catalog to include the expedited access indicator associated with the target data object unless the target data object meets certain disqualifying criteria.

11. A logic circuit of multiple interconnected electrically conductive elements configured to perform operations to manage a data management system comprising direct-access storage constituting a primary level of storage and multiple removable data storage media constituting an auxiliary level of storage, the system including an inventory containing metadata identifying data objects contained in the auxiliary level, the operations comprising:

responsive to each recall request comprising a request to copy a target data object from the auxiliary level to the primary level, performing recall operations comprising;

determining whether the target data object meets prescribed future-reconnection criteria, and if so, updating a catalog to include an expedited access indicator associated with the target data object;

copying the target data object from the auxiliary level to the primary level;

updating the inventory to invalidate metadata identifying the target data object in the auxiliary level;

responsive to migration requests each comprising a request to copy a specified data object from the primary level to the auxiliary level, performing migration operations comprising;

determining whether the catalog contains an expedited access indicator associated with the specified data object;

if the catalog contains an expedited access indicator associated with the specified data object, determining whether restoration of a copy of the specified data from the auxiliary level is possible, and

if restoration is not possible, performing a full migration comprising copying contents of the specified data object from the primary level to the auxiliary level;

if restoration is possible, performing a shortcut migration comprising updating the inventory to restore invalidated metadata identifying the specified data object in the auxiliary level without copying the specified data object from the primary level to the auxiliary level; and

if the catalog does not contain an expedited access indicator associated with the specified data object, copying content of the specified data object from the primary level to the auxiliary level.

12. A data storage system, comprising:

a primary storage level comprising direct-access storage media;

an auxiliary storage level comprising removably mounted storage media;

an inventory containing metadata identifying data objects contained in the auxiliary level;

a storage manager, configured to perform operations to manage access of the primary and auxiliary storage levels, the operations comprising;

responsive to each recall request comprising a request to copy a target data object from the auxiliary level to the primary level, performing recall operations comprising;

determining whether the target data object meets prescribed future-reconnection criteria, and if so, updating a catalog to include an expedited access indicator associated with the target data object;

copying the target data object from the auxiliary level to the primary level;

updating the inventory to invalidate metadata identifying the target data object in the auxiliary level;

responsive to migration requests each comprising a request to copy a specified data object from the primary level to the auxiliary level, performing migration operations comprising;

determining whether the catalog contains an expedited access indicator associated with the specified data object;

if the catalog contains an expedited access indicator associated with the specified data object, determining whether restoration of a copy of the specified data from the auxiliary level is possible, and

if restoration is not possible, performing a full migration comprising copying contents of the specified data object from the primary level to the auxiliary level;

if restoration is possible, performing a shortcut migration comprising updating the inventory to restore invalidated metadata identifying the specified data object in the auxiliary level without copying the specified data object from the primary level to the auxiliary level; and

if the catalog does not contain an expedited access indicator associated with the specified data object, copying content of the specified data object from the primary level to the auxiliary level.

13. A data storage system, comprising:

primary storage means for providing direct-access storage and retrieval of data;

auxiliary storage means providing storage and retrieval of data upon removably mounted storage media;

inventory means for storing metadata identifying data objects contained in the auxiliary storage means;

storage managing means for managing access of the primary and auxiliary storage means by;

responsive to each recall request comprising a request to copy a target data object from the auxiliary storage means to the primary storage means, performing recall operations comprising;

determining whether the target data object meets prescribed future-reconnection criteria, and if so, updating a catalog to include an expedited access indicator associated with the target data object;

copying the target data object from the auxiliary storage means to the primary storage means;

updating the inventory means to invalidate metadata identifying the target data object in the auxiliary storage means;

responsive to migration requests each comprising a request to copy a specified data object from the primary storage means to the auxiliary storage means, performing migration operations comprising;

determining whether the catalog contains an expedited access indicator associated with the specified data object;

if the catalog contains an expedited access indicator associated with the specified data object, determining whether restoration of a copy of the specified data from the auxiliary storage means is possible, and

if restoration is not possible, performing a full migration comprising copying contents of the specified data object from the primary storage means to the auxiliary storage means;

if restoration is possible, performing a shortcut migration comprising updating the inventory to restore invalidated metadata identifying the specified data object in the auxiliary storage means without copying the specified data object from the primary storage means to the auxiliary storage means; and

if the catalog does not contain an expedited access indicator associated with the specified data object, copying content of the specified data object from the primary storage means to the auxiliary storage means.