Emc Corporation

Edward L Thigpen

Helen S Raizen

Michael E Bappe

Cesareo Contreras

Micheal E Bappe

A data migration operation uses an error flag to protect against data corruption. During write cloning states, the error flag is set and only allowed state transitions are performed, including a non-error transition to a committed state when no device fault is recorded for a target storage device and an error transition to a setup state when a device fault is recorded for the target storage device. In a clean system shutdown, a shutdown procedure records a detected target storage device fault and clears the error flag; the recorded device fault later forces the error transition of the migration operation. During the system startup, if the error flag is set then a target storage device fault is recorded to likewise later force the error transition of the migration operation, on the assumption that a detected fault may exist but be unrecorded because the shutdown procedure did not complete during shutdown.

Maintaining data integrity in data migration operations using per-migration device error flags

A method of performing data migration from a source storage device to a target storage device in a failover cluster includes use of a roll-forward flag to signal successful completion of a migration operation from a migration node to failover nodes of the cluster, reliably controlling host access to the target storage device to ensure that it is used only when it has been successfully synchronized to the source storage device and a commit operation has occurred that ensures that subsequent read and write operations are directed exclusively to the target storage device.

Non-disruptive storage device migration in failover cluster environment

Systems and methods are provided for maintaining data integrity in the event of device write failures during a non-disruptive migration. In one embodiment, a computer-implemented method is provided. According to the method, a filter driver in a kernel may clone an application write to both a source storage device and a target storage device. The method may detect whether the cloned application write to the source storage device or the cloned application write to target storage device failed. When the cloned application write to the source storage device or the cloned application write to target storage device failed, the method may allow application reads from only one of the source storage device and the target storage device thereafter.

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Raleigh, NC, United States of America

Edward L Thigpen