US 6,108,748 A · System and method for on-line, real time, data migration

Abstract

A system and method for providing on-line, real-time, transparent data migration from an existing storage device to a replacement storage device. The existing and replacement storage devices are connected as a composite storage device that is coupled to a host, network or other data processing system. The replacement storage device includes a table which identifies data elements that have migrated to the replacement storage device. When a host system makes a data transfer request for one or more data elements, the replacement storage device determines whether the data elements have been migrated. If the data elements have migrated, the replacement storage device responds to the data transfer request independently of any interaction with the existing storage device. If the data elements have not migrated, the replacement storage device migrates the requested data elements and then responds to the data request and updates the data element map or table. When not busy servicing other requests, the replacement storage device operates in a background mode to migrate data elements so the data migration can occur concurrently with and transparently to system operations.

Claims11

Dependent claims

Data migration apparatus for migrating data from a donor disk array storage system to a replacement disk array storage system while continuing to respond to write requests from a host computer coupled to said replacement disk array storage system said apparatus comprising:

A) a data store, and
B) a migration control that connects to the host computer and the donor disk array storage system thereby to redirect input-output requests from the host computer to the replacement disk array storage system and that migrates data from the donor disk array storage system to the replacement disk array storage system under the control of the replacement disk array storage system and that responds to data write requests from the host computer to locations in the replacement disk array storage system to which data has not yet been migrated by transferring the data associated with the write request to the replacement disk array storage system and by preventing the transfer of corresponding data from the donor disk array storage system to the replacement disk array storage system.

A method of migrating data from a donor disk array storage system, that responds to input-output requests including write requests from a host computer, to a replacement disk array storage system that is to replace the donor disk array storage system while continuing to respond to write requests from the host computer, said method comprising the steps of:

A) connecting said replacement disk array storage system to the host computer and to the donor disk array storage system to receive input-output requests from the host computer whereby the donor disk array storage system ceases to respond directly to input-output requests from the host computer,
B) migrating data from the donor disk array storage system to the replacement disk array storage system under the control of the replacement disk array storage system concurrently with and independently of any input-output requests directed to the replacement disk array storage system;
and
C) responding to data write requests from the host computer to locations in the replacement disk array storage system to which data has not yet been migrated by transferring the data associated with the write request to the replacement disk array storage system and by preventing the transfer of corresponding data from the donor disk array storage system to the replacement disk array storage system.

1 more element

Dependencies are inferred from the claim text.

System and method for on-line, real time, data migration

Life of this patent

System and method for on-line, real time, data migration

Life of this patent

Abstract

Claims11