Non-disruptive storage device migration in failover cluster environment
First Claim
1. A method of non-disruptively migrating contents of a source storage device to a target storage device in a data processing system having a set of host computers organized into a failover cluster, the host computers including a migration node and one or more failover nodes, the migration node executing an application program accessing the source storage device via a device name, each failover node being operative to begin execution of the application program upon failure of the migration node, comprising:
- creating metadata and a roll-forward flag, the metadata indicating that a migration operation is in progress, the roll-forward flag initially being reset, the metadata also including access control data initially set to allow access to the source storage device and disallow access to the target storage device;
subsequently synchronizing the target storage device to the source storage device and configuring the target storage device to each of the failover nodes, the synchronizing leading to a source-selected operating state in which read and write operations continue to be directed to the source storage device and write operations are also duplicated to the target storage device; and
subsequently performing a commit operation causing subsequent read and write operations to be directed exclusively to the target storage device, the commit operation including (i) setting the roll-forward flag, (ii) setting the access control data to disallow access to the source storage device and allow access to the target storage device, and (iii) changing or remapping the device name to cause the application program to access the target storage device instead of the source storage device;
wherein the migration node is operative when the source storage device is coming online (i) if the roll-forward flag is not set, to abort the migration operation and maintain the initial setting of the access control data allowing access to the source storage device and disallowing access to the target storage device, and (ii) otherwise if the roll-forward flag is set, to ensure completion of the commit operation;
and wherein each failover node is operative when the source storage device is coming online and the roll-forward flag is set, to (i) set the access control data to disallow access to the source storage device and allow access to the target storage device, and (ii) change or remap the device name to cause an application program executing on the failover node to access the target storage device instead of the source storage device.
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Accused Products
Abstract
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.
30 Citations
14 Claims
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1. A method of non-disruptively migrating contents of a source storage device to a target storage device in a data processing system having a set of host computers organized into a failover cluster, the host computers including a migration node and one or more failover nodes, the migration node executing an application program accessing the source storage device via a device name, each failover node being operative to begin execution of the application program upon failure of the migration node, comprising:
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creating metadata and a roll-forward flag, the metadata indicating that a migration operation is in progress, the roll-forward flag initially being reset, the metadata also including access control data initially set to allow access to the source storage device and disallow access to the target storage device; subsequently synchronizing the target storage device to the source storage device and configuring the target storage device to each of the failover nodes, the synchronizing leading to a source-selected operating state in which read and write operations continue to be directed to the source storage device and write operations are also duplicated to the target storage device; and subsequently performing a commit operation causing subsequent read and write operations to be directed exclusively to the target storage device, the commit operation including (i) setting the roll-forward flag, (ii) setting the access control data to disallow access to the source storage device and allow access to the target storage device, and (iii) changing or remapping the device name to cause the application program to access the target storage device instead of the source storage device; wherein the migration node is operative when the source storage device is coming online (i) if the roll-forward flag is not set, to abort the migration operation and maintain the initial setting of the access control data allowing access to the source storage device and disallowing access to the target storage device, and (ii) otherwise if the roll-forward flag is set, to ensure completion of the commit operation; and wherein each failover node is operative when the source storage device is coming online and the roll-forward flag is set, to (i) set the access control data to disallow access to the source storage device and allow access to the target storage device, and (ii) change or remap the device name to cause an application program executing on the failover node to access the target storage device instead of the source storage device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computerized device operable as a migration node in a set of host computers organized into a failover cluster, the host computers also including one or more failover nodes, the migration node executing an application program accessing a source storage device via a device name, each failover node being operative to begin execution of the application program upon failure of the migration node, comprising:
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memory storing computer program instructions; one or more processors; input/output interface circuitry for connecting the computerized device to the other host computers and to the source storage device and to a target storage device; and interconnect circuitry coupling the memory, processors and input/output interface circuitry together, wherein the processors are operative to execute the computer program instructions from the memory to cause the computerized device to non-disruptively migrate contents of the source storage device to the target storage device by; creating metadata and a roll-forward flag, the metadata indicating that a migration operation is in progress, the roll-forward flag initially being reset, the metadata also including access control data initially set to allow access to the source storage device and disallow access to the target storage device; subsequently synchronizing the target storage device to the source storage device, the synchronizing leading to a source-selected operating state in which read and write operations continue to be directed to the source storage device and write operations are also duplicated to the target storage device; and subsequently performing a commit operation causing subsequent read and write operations to be directed exclusively to the target storage device, the commit operation including (i) setting the roll-forward flag, (ii) setting the access control data to disallow access to the source storage device and allow access to the target storage device, and (iii) changing or remapping the device name to cause the application program to access the target storage device instead of the source storage device; wherein the migration node is operative when the source storage device is coming online (i) if the roll-forward flag is not set, to abort the migration operation and maintain the initial setting of the access control data allowing access to the source storage device and disallowing access to the target storage device, and (ii) otherwise if the roll-forward flag is set, to ensure completion of the commit operation; and wherein each failover node is operative when the source storage device is coming online and the roll-forward flag is set, to (i) set the access control data to disallow access to the source storage device and allow access to the target storage device, and (ii) change or remap the device name to cause an application program executing on the failover node to access the target storage device instead of the source storage device. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification