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Method for uninterrupted migration of data between a file system and a device

IP.com Disclosure Number: IPCOM000218318D
Publication Date: 2012-Jun-01
Document File: 2 page(s) / 25K

Publishing Venue

The IP.com Prior Art Database

Abstract

A mechanism allows for uninterrupted migration of an application's data without interruption.

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This is the abbreviated version, containing approximately 51% of the total text.

Page 01 of 2

Method for uninterrupted migration of data between a file system and a device

When one migrates a data to or from a set of devices to a set of files in a file system, the application must be halted, the data backed up, and a restore operation must be run to the target location. This is not optimal.

The disclosed idea is to provide an uninterrupted migration between a device and a file system. This is accomplished by adding callouts in both the logical file system and a device IO subsystem. The file system and device in this context can be thought of as containers of data. These entry points are used for migration from one container to another.

A data migration is initiated between an original container and a migration container. In reality there are several containers that need to be atomically migrated from one container to another, at which point the call outs in the original container are activated.

When a read request is received at the original container that container will retrieve the data requested. If the data requested (region) has been written in the migration container, then the data requested is returned to the requester. If the data request (region) has not been written in the migration container then the data is written to the migration container after the data is written to the migration container the region written is recorded and the data request is return to the requester.

When a write request is received at the original container that container will write the data into the original container and the migration container. When both writes are complete the region in the migration container is recorded and write status is returned to the write requester.

When the original container has been completely copied to the migration container all requests are now routed to the migration container and the original container will be removed. For multiple containers the all of the original containers must be completely copied to their migration container before any original container routes requests to the migration containers.

An example: if the administrator is migrating a database from files in a file system to a set of devices or devices to files all of the set of containers must be migrated to have a valid database.

First one must insert working callouts within the file system layer and the device IO layer so as the application issues writes to the original container. These writes are written to both the original container and the migration container (container to be migrated to). On a read the data read...